Biotic invasion

Some of the most pressing problems in ecology get little discussion in the public realm. Such is the case with invasive plants and animals. The fall season brought visual reminders of the relentless expansion of this problem in the northeastern US, and other parts of the country are not doing much better. This year’s poster child plant was, for me, Japanese Knotweed.

Japanese Knotweed. October, Danville, Vermont

After the deciduous forest dropped its leaves, knotweed stood out like a sore thumb, with its coppery color, its broad leaves, and its domination in the patches it has conquered, where no other plant, let alone native plant, can survive.

The Winooski River flowing through Marshfield, Vermont. The copper-colored stand at center is Japanese Knotweed.

Our wonderful local broadcast program, Brave Little State, just did a really nice piece on the infernal Japanese Knotweed. It’s been in Vermont for about a century. Growing steadily, it now occupies streambanks and roadsides in almost every part of Vermont.  The problem is largely independent of anthropogenic climate warming.

Many people, my late mother included, dismiss the introduction of foreign plants as a charming and inoffensive little issue. After all, there are so many more pressing problems, like the re-election of Trump and the destruction of property by floods. But one does not have to look very hard to find documented cases of invasive plants costing billions of taxpayer dollars to fight. Or introduced pests that threaten agricultural products, which raise the cost of your grocery bill.

Many, perhaps all, invasive plants are champions of the mechanism of spread by disturbance. When a creek floods and tears out a section of vegetation on the bank, the seeds of the invasives are quick to take advantage. With the intense summer rainstorms of 2023 and 2024, Danville and St Johnsbury are now bearing witness to the power of Japanese Knotweed to become the sole occupant of large stretches of streambank. But these invasives don’t care if the disturbance is natural or man-made. Roadsides that have been worked over by earth-moving equipment are just the right stimulus for a new patch. Often it is a homeowner improving the view by carelessly tearing out trees and bushes, and buying into a problem that will take thousands of dollars to remedy.

Residential property in Lyndon, Vermont, succumbing to a forest of Japanese Knotweed.

To emphasize the nature of this problem for native plants, it’s important to realize that knotweed and other invasives displace natives completely. If we did nothing at all, every streambank in Vermont would end up being 100% knotweed – a catastrophe of immense consequence. All of the grasses, sedges, forbs, and trees that currently provide shelter, food, and camouflage for native wildlife would be gone. Japanese Knotweed provides none of these because there has been no evolutionary overlap with native wildlife. Our river banks would be no better than if paved with asphalt. Knotweed does not stabilize the stream banks that it smothers: it leads to further flood erosion, which makes space for even more knotweed. Clever, positive-feedback strategy!

There is more to write about invasive plants and animals than there is ink to write with. Many of them exact enormous costs on us. There are also many cases where the costs are yet to come. Perhaps one of these is the Asian Ladybug, a yearly visitor to our house and yard. Superficially, they look just like native ladybugs – not unpleasant at all. When the weather turns cold, though, these pests invade our house in numbers that strike fear and loathing in us. Their extreme abundance makes me worry about which native insects have been displaced to accommodate them. This may be an issue not well studied.

Asian Ladybugs trying to winter in my garage, November 2024.

What can you do? First of all, don’t be part of the problem of propagation. Look in your own yard and identify unfamiliar plants. We use the phone app Seek, which taps into a phenomenal knowledge bank about plant identification and distribution. Yank any plants that are labelled by Seek as “Introduced” (although check the map and the written description to be sure). Be careful about plants that you buy at a commercial nursery. Ask the salesman about the potential for that attractive little plant in the pot to become invasive. If you get a shrug of the shoulders, assume the worst, and put it back on the shelf. When you ask a lot of questions, you will begin to discover the fact that only a few nurseries exist that specialize in native plants, and they deserve the money from your wallet. Many of the sprawling, bargain-basement commercial plant sellers (including Lowe’s and Home Depot) are not reputable. In our area, Fedco is a good one. Prairie Nursery delivers native seeds and plants from their Wisconsin location. In New Mexico, for years we went exclusively to Plants of the Southwest and Agua Fria Nursery. They are more expensive, but there is a good reason for that, since they expend a lot more effort investigating problems and nursing along the slow-growing natives.

Second, give your support to local eradication programs. These government-sponsored efforts use taxpayer money to do their work. They are the only effective means of preventing future invasive problems. The programs are expensive, but will save compared to much larger programs that start after the problem has gotten out of hand. One of my favorite riparian birding spots in Galisteo, New Mexico was the site of a Russian Olive eradication effort to restore willows and cottonwoods. When the heavy equipment finished its job of pulling stumps, a few locals were upset that the floodplain looked denuded. They should have known better. I’ve been told that it is now a much wetter environment, spurring the growth of valuable and declining riparian species of trees and shrubs. On our trip to Kruger National Park in South Africa, we learned that  eradication of exotics is a large and important part of the budget. Our guide pointed to the many roadside crews we saw, busy with tree and plant removal. This effort is an important source of income for local workers.

Third, educate yourself about invasive issues in your area, and become an advocate for eradication. Support the removal of feral cats in your town. In the world of birds, one effort that has run into misguided opposition is the removal of Mute Swans. People who don’t know take notice of their elegant form and assume they deserve protection. They do not. They were introduced to North America over a century ago, and are now displacing native ducks and geese, as well as native swans on wintering grounds. They are shockingly aggressive toward ducks and even people (when nesting), and they are overeating aquatic plants that natives rely on. Animal rights groups have filed lawsuits  to prevent agencies from shooting them, which only further reduces the budgets needed to restore habitat. Feral horses roam parts of the western US, and contribute to overgrazing on public lands. Perhaps the most distressing example of invasive animals is the case of feral pigs in Hawaii, which have decimated the fragile ecosystem of the islands by their tendency to rip out roots. Regrettably, many people find it fun to hunt them, and this lobby has prevented the removal of the pigs. An insane tragedy of misunderstanding. Be open to the kind of eradication measures that may at first seem aggressive. Chemicals, hormonal injections, trapping, shooting, even (as in the case of Tamarisk) the introduction of another pest species. Be patient and listen to the agency personnel’s case carefully – they have been studying the issue far longer than you have.

Ammodramus

 Ammodramus

This October, we had the good fortune to get looks at a Nelson’s Sparrow. It was a rare opportunity to experience one of the most secretive birds in North America. It marked only about the fourth time I have seen one of these stunning, intricately marked, colorful seed foragers. Other birders had found this individual on a farm about an hour south of us. The orange-colored wonder has been there for about a week, a surprisingly long stay this far north for a long-distance migrant, headed for the Gulf of Mexico or the southeast coast of the US. They breed along the shores of Hudson Bay and in the great plains in far northern Canada. Another race of Nelson’s breeds along the coast of Maine.

Nelson's Sparrow, Tullando Farm, Orford, New Hampshire, Oct 2024.

Nelson’s is in a distinctive group of sparrows that are all beautifully patterned and maddeningly hard to see. I like to refer to them as Ammodramus, a genus name that once contained seven similar-looking species. (The name is no longer accurate, since taxonomic gymnastics has resulted essentially in a split between Ammodramus, Ammospiza, and Centronyx. But Ammodramus is a convenient shortcut name, if not entirely accurate. See J.D. Rising and D.D. Beadle, The Sparrows of the United States and Canada, p. 143.) Ammodramus is Greek for "sand runner," which would seem to refer to its habit of walking in marshes in winter.

In my early years of birding, I would flip through the field guide and wonder about the things I still had not seen. The couple of pages of Ammodramus seemed like a complete mystery. Their orange-tinged heads made them look different from all other sparrows. They did not seem to come up in conversation with birders because nobody had a reliable location to go see one. All of them have a habit of staying hidden in thick vegetation in marshy areas or in dense grasslands. It would be many years before I would manage to get looks at them, always by way of information shared among birders.

The most common of the Ammodramus is Grasshopper Sparrow. It also has the largest range, inhabiting most of the North American continent, save for the areas that are grass-free due either to low rainfall or overgrazing or both. In the 1980s-1990s, they were breeding birds at the Las Vegas National Wildlife Refuge, a great place for birding not far from where I lived. This refuge is grazed by cattle, but lightly, and it managed to hang on to some quite fine patches of tall grasses. The decline of Grasshopper Sparrow at this location is mysterious; I am guessing that some complex set of climate factors is to blame, or some subtle shift in the species makeup of the grasses. But the sparrow can still be found in many parts of the country. Sadly, however, surveys demonstrate a national decline in numbers that is the subject of current investigation.

Grasshopper Sparrow. Ohkay Owingeh pueblo, New Mexico, April 2018.

Grasshopper Sparrow showing its characteristic flat head.
Ohkay Owingeh pueblo, New Mexico, April 2018.

Seaside Sparrow, the least colorful member of Ammodramus, is reasonably reliable in Delaware marshes, but restricted to shoreline habitats to a remarkable extent – it never shows up anywhere else.

Seaside Sparrow, Marvel Saltmarsh Preserve, Delaware, May 2021.

So that’s it. The rest of the Ammodramus fall into the category of Ridiculously Hard to See. They don’t move around or sing loud like other sparrows. They breed in far-away lands, and winter at scattered places in the Southeast where birders seldom go. On migration, they generally don’t stay in known locations. They stay under cover – like, all day, every day. They see birders approaching from a long distance, and start to ridicule us. “Hey, it’s about time to sit in this bush and preen for a while,” they think. “That dude with the binoculars doesn’t stand a chance.”

Saltmarsh Sparrow is so restricted in distribution now that I know of only one location for it: the Marvel Saltmarsh Preserve in Slaughter Beach, Delaware. This spot was saved from the bulldozer in the 1980s. Today it is a beautiful expansive stretch of saltmarsh, filled with bitterns rails, herons, and harriers.

Marvel Saltmarsh Preserve. May 2021.

 Stand on the boardwalk here and look out for the tiny shaking of a branch that reveals a bird. I have heard them sing, or “sing,” only at sunrise and well after sunset. The “song” is a strange, mildly insect-like exhalation of breathy sound. (I suspect the song evolved to propagate in the frequent winds that blow.)

Saltmarsh Sparrow, Savage's Ditch, Delaware, November 2020. There are a few records here.

Baird’s Sparrow, Henslow’s Sparrow, and LeConte’s Sparrow are the midwestern members of Ammodramus. Baird’s moves south in the fall and scatters into huge areas of scrub (or former Chihuahuan desert grassland) of the American southwest and (mostly) Mexico. They like to stay on the ground when wintering, and usually walk away from an approaching birder and disappear between plants. This area has been devastated by livestock grazing, making the birds even more scarce than they would otherwise be. My only sighting lasted a fraction of a second, a bird scampering away from me after an five-hour search in early January near Deming, New Mexico. Henslow’s Sparrow is rapidly declining because of grassland loss to agriculture and urbanization. My only sighting was in far western Maryland, where coal mining sites have been converted to artificial grasslands high in the Appalachians that seem to substitute for their preferred prairie habitat.

LeConte’s Sparrow breeds in the Midwest (mostly Canada) and winters in the American southeast, where it is so thinly distributed that it is hard to locate. It may be the most beautiful species in a genus known for its good looks. I have observed it only twice, when a migrant bird stopped for a few days beside a hay field in Maryland, and when a few of them accidentally found themselves beside a reservoir in eastern New Mexico for the winter (thanks, Bill West). The species seems to be holding its own in numbers, but then again, very little is known about it and future research might paint a different picture.

LeConte's Sparrow, Mt. Pleasant Farm, Maryland, Nov 2020.

Nelson’s Sparrow allegedly winters in the marshes in Delaware. But very few are actually detected each winter. I found my first one at a southern Delaware marsh known as Savage’s Ditch, when it raced ahead of me on a wet path and perched for a minute or two about a foot off the ground, on a mostly obscured perch. They occur annually in a marsh near Burlington known as Delta Park, but not when I have visited! So it was good news indeed to hear that we could enjoy the bird a second time at the edge of a large dairy farm in New Hampshire. This bird is using a tiny fragment of habitat, a muddy puddle where runoff accumulates and a few tall grasses grow beside a cornfield (yet another example of opportunism on migration). We stopped there and waited for a half hour, before it was betrayed by tiny movements of branches. Characteristically, it hopped just a few inches from branch to branch, and also walked a bit on the mud while looking for seeds. It never stayed in view for more than a few seconds. (I got photos only by way of a determined effort.) The golden color of the bird’s head seems to scream out “I’m not like the other sparrows.” This pattern is clearly camouflage for when it is wintering among brown stalks in the marsh. But its beauty is obscured by its habit of staying deep in the vegetation, and refusing to produce the kinds of chips that the common Song and Swamp sparrows give so frequently in the same habitat. Nelson’s Sparrows keep it quiet and mysterious.

The loss of marshes, especially salt marshes, is one of the most serious environmental problems of our time. I am still educating myself on the issue, especially on salt marsh restoration. Here is some of the latest information on measuring the loss of global salt marshes. And here is a small sample of information on what is being done to restore former salt marshes.

 For further reading about Ammodramus, be sure to check out the book by James Rising and David Beadle, The Sparrows of the United States and Canada. Shockingly, it seems to be out of print, but there are copies available on the usual used-book websites.

 

Opportunism

 Opportunism and bird migration

Pondicherry National Wildlife Refuge, New Hampshire

Migration for this autumn season brought a few nice surprises to our area. In late August and early September, we enjoyed the usual warbler show in our driveway, where a line of Balsam Firs provide a suitable place to forage. We had Cape-May Warblers, Bay-breasted Warblers (a few with some bay still on the flanks), American Redstarts, many Black-throated Green Warblers, one snazzy Wilson’s Warbler, Black-and-white Warblers, Tennessee Warblers, Nashville Warblers, Common Yellowthroats, Northern Parula, Magnolia Warblers, Blackburnian Warblers, Chestnut-sided Warblers, Yellow-rumped Warblers, Red-eyed Vireo, Blue-headed Vireos, and a few Scarlet Tanagers. Not bad.

Wilson's Warbler, Danville, Vermont. Peeking out from the interior of the vegetation.

Black-throated Green Warbler in its fall plumage. Newport, Vermont

Each migration season brings a reminder that birds have been such a successful life form due in part to a facility for opportunism. Migrating birds need stopover points with abundant food to fuel the long journey. They will be found in the kind of undisturbed habitat patches that you read about in field guides. But in addition, they are found in transient patches that just happen to arise on the route. The birds don’t seem to care whether the food (insects and caterpillars, for warblers and vireos) is provided by mature forests or by gardens and back yards. Shorebirds, herons, and egrets are drawn to healthy wetlands, but man-made wet areas will do, at least for a few hours or days of the journey. To be sure, all forms of wildlife seize on opportunities to feed, but the special mobility conferred upon birds gives them an extraordinary ability to find the smallest bit of far-flung habitat.

The local community of birders in my area has helped me to find a few of these patches. A cornfield beside the Passumpsic River in Saint Johnsbury has drawn in dabbling ducks in spring and fall, when either rain or snowmelt fills it up to a suitable level. Fruit trees around our grocery store parking lot sometimes bring in Bohemian Waxwings in the winter. Shorebirds will make use of flooded farm fields, too. I have spent time tracking down Upland Sandpipers and Buff-breasted Sandpipers in Delaware ag fields (especially sod farms), and I’ve seen Greater and Lesser Yellowlegs and Killdeer in fields close to home.

Birders are no less opportunistic than the birds. If the birds happen to be there, why not stop and look at them? Even when the scenery is – ahem -- not winning any awards, shall we say.  In New Mexico, west Texas, and Arizona, sewage treatment plants become an accidental food source to shorebirds, dabbling ducks, and herons. The Tucson sewage plant is famed among birders: I went there once for a Least Grebe, a rarity from south of the border. (It is comically named "Sweetwater wetlands.") We once ventured to the sewage plant of forlorn Lordsburg, New Mexico to see a Black-bellied Whistling Duck. Similar ponds in New Mexico gave me a chance to see White-rumped Sandpiper, Semipalmated Plover, Short-billed Dowitcher, Wilson’s Phalarope, Red-necked Phalarope, Baird’s Sandpiper, and Solitary Sandpiper. All of these were in places that were arid for tens of kilometers in all directions. (Except for the Rio Grande, which does not form mudflats that attract shorebirds, having been channelized by order of state legislatures.) It demonstrates how shorebirds, while flying thousands of miles south in the fall, mostly over dry land of the interior US, will not pass up an opportunity to exploit a wetland, small though it may be. A sewage pond lacks mud, the key ingredient for shorebird dinner, but it does possess insects in copious numbers.

In Vermont this fall, a birder alerted me to a Solitary Sandpiper in a flooded pasture nearby. Intrigued, I went there and found a pair of Stilt Sandpipers, a rarity away from lakes and oceans (at least in the East). The spot, on Old Silo Road near Barnet, is interesting. In the floodplain of the Passumpsic River, water collects there in spring and fall for a few weeks at most, before disappearing by evaporation and slowly draining to the river. Hoof action from the cows gives rise to mud and shallow puddles that mimics the mudflats around marshes. It becomes a bit of a shorebird magnet. Solitary Sandpipers were there for the whole season. The pair of Stilt Sandpipers stayed only a day (so far as we know). But what a day it was, for the nutritional requirements of a long-traveling sandpiper. Stilt Sandpipers breed in the Canadian arctic, and then fly as far south as Argentina – thirteen thousand kilometers to the wintering grounds. That requires a whole lot of calories.

Stilt Sandpipers in a farm field, Barnet, Vermont

Other birders found a group of gulls at Moore Dam, on the Connecticut River on the state line between New Hampshire and Vermont. I have visited the spot many times in the last few years, with almost no result. The Moore Reservoir just doesn’t seem to do much for avian wildlife. My suspicion is that the water level is yanked up and down to satisfy hydroelectric power demand, and this wreaks havoc with the aquatic food chain. Industrial pollution from past mill operations is also a factor. Ducks and loons just can’t find much to sustain them. Gulls have been few and far between. But in late August, a small group of gulls found their way to the dam, perching on those red buoys guarding the dam structures. The birders found the usual Ring-billed Gulls and Herring Gulls, but also a few Great Black-backed Gulls. The last of these is mostly coastal in distribution, but also makes use of the Great Lakes in winter, and sometimes the Connecticut River farther south. A sharp-eyed observer found that one of the larger gulls didn’t quite fit the pattern, and called out a Lesser Black-backed Gull among them – a coastal bird for sure. That drew another birder, who noticed a small, brown-colored bird in the flock that proved to be a juvenile Laughing Gull. Another coastal species. Yet another birder noticed a tern, which proved to be a juvenile Forster’s Tern. This one uses the interior of the continent routinely, but is rare this far north. These birds were joined by one juvenile Bonaparte’s Gull, an uncommon visitor to the area.

Laughing Gull, out of place at Moore Dam in New Hampshire

What was going on here? A few days prior to the gulls’ appearance, Hurricane Debby pushed through the southeastern US. (It hit South Carolina in the first week of August.) Storms have a way of stirring things up for birds. High winds will push a few of them northward. Some of the birds, especially juveniles with no experience, will drift inland. When the winds dissipate, the birds will find some suitable patch of habitat to land on. In this case, the Moore Reservoir on the Connecticut River was the draw. I observed this flock for several hours spaced across a few weeks of time, and I almost never saw them feeding successfully. They perceived the large body of water to be appropriate, but (being mostly juveniles) they did not recognize that there was very little food there. They eventually shipped out and likely joined their compatriots in better parts to the south. Opportunism drove them to make use of Moore Reservoir, but it was a short-lived impulse.

The ultimate example of opportunistic use of “habitat” must be an example from the northeastern US. Dairy farms generate a lot of manure, which is collected and processed for spreading on hay and corn fields. Manure is initially stored in an open pit, where it becomes a breeding ground for insects. Passing shorebirds take notice. In Vermont, a few of these pits become some of the best places to find shorebirds, since natural mudflats are almost impossible to find. This fall, I found a juvenile Baird’s Sandpiper at a pit near Hardwick. There were large numbers of Least, Semipalmated, Solitary, Spotted Sandpipers, and Killdeer at the same spot. Birding at a manure pit makes birding at a sewage plant seem positively fragrant.

Baird's Sandpiper, at a manure pit near Hardwick, Vermont

Clearly, patches of habitat are needed by migrant birds moving long distances in August, September, and October. What can humans do to help? First of all, we need to care for our wetlands. We have been altering them for human uses and human convenience for centuries. Many wetlands – thousands of square miles worth – have been altogether destroyed. Many have been modified in a quest to reduce mosquito-borne malaria. Many midwestern wetlands have been filled in to grow crops. Although it is hard to quantify, these actions have certainly resulted in population reductions for birds amounting to millions, and perhaps a billion. The modern form of ecological science has begun to quantify the damage, but much of the loss cannot easily be reversed without economic disruption to coastal city populations of people like you and me.

Second, we need to improve the way we manage the wetlands that still remain. Water levels can theoretically be managed carefully to sustain mudflats. This is true for both private and public lands. Reservoirs are mostly managed by the Army Corps of Engineers and the Bureau of Reclamation. Both have dreadful histories of monitoring wildlife populations on and near reservoirs and in the rivers they are situated on. The agencies comply with the Endangered Species Act, but just barely, and often only under pressure from conservation group lawsuits. Many hydroelectric dams in the east, like Moore Dam, are privately owned, and conservation goals are not valued highly.

One might expect better performance from the US Fish and Wildlife Service, which operates National Wildlife Refuges. Indeed, many NWRs today contain some of the best habitat in the country for waterfowl. But there are still problems. NWR managers normally feel that their mandate is restricted to ducks and geese, which generate significant revenue through hunting. Water in NWRs is managed to optimize duck habitat, but this doesn’t always work for shorebirds. Production of mudflats requires attention to the timing and amounts of water in impoundments. The showpiece for shorebird management is the legendary Bombay Hook NWR in Delaware. (The odd name seems to come from a dark chapter in its history, when the wetland was used to train bomber pilots for World War II combat.)

Scanning for shorebirds at Bombay Hook NWR, Delaware

Congress really needs to act to change the USFWS mission to enhance and preserve shorebird habitat on all refuges, even if waterfowl habitat suffers a bit. Congress should also force private dam owners to examine their impacts on wildlife. They operate at the behest of the people on whose land they occupy, so corporate goals should not be allowed to trump the public interest.

A mass of shorebirds at Bombay Hook NWR, Delaware, May 2024. Dunlins, Semipalmated Sandpipers, Short-billed Dowitchers, Semipalmated Plovers, and Black-bellied Plovers.

Sage Grouse

 Sage Grouse

In nearly four decades of birding, I had never managed to make contact with Sage Grouse. It is mostly a resident of Wyoming, southern Idaho, eastern Montana, and eastern Washington, places to which I have rarely or never ventured. This summer we traveled to northern Colorado to see them at the southeastern edge of the bird’s range.

Greater Sage-grouse, Coalmont

The Sage Grouse is well named.  It is intimately tied to sagebrush, especially the species known as Big Sagebursh, Artemisia tridentata (the leaf being three-toothed in shape). Before European settlement, tridentata occupied vast areas of the American west (270 million acres), and it was healthy. (Varieties of this shrub can be bought in nurseries in New Mexico, and they do well in the yard with no supplemental water – as we learned when living there.) This made the Sage Grouse happy and it thrived. There are several closely related species of grouse in North America, likely deriving from some original grouse-like bird before specializing into the continent’s unique habitats. Sage Grouse decided to settle down in the semi-arid, mostly flat areas between mountain ranges in the upper northern portions of the American west, including nearby parts of Canada. The vast regions of Big Sagebrush were also colonized by specialized bunchgrasses that occupied the places between shrubs. The Sage Grouse found good use for that too, with the tall grasses helping to hide chicks from predators. In the long cold and windy winters of the region, the Sage Grouse learned to survive by eating sage leaves. The unique characteristics of this habitat caused the species to differentiate from the other grouse like Dusky Grouse, which kept to the mountains, and Greater Prairie Chicken in the tallgrass prairie to the east.

Native American tribes would have been intimately familiar with the Sage Grouse. The lavish and energetic displays of males during courtship must have been witnessed and marveled at by generations of tribal people. It doesn’t seem too far-fetched to imagine that spring-season Sage Grouse dances at lek sites were part of the inspiration for tribal dances that one can still experience today. The tribes would have hunted the abundant grouse in appropriate season, and would have treasured the breeding plumes of the male birds as precious and rare. They would have been expertly informed about where the grouse thrived and what it needed to perpetuate.

These lessons, like so many of the period, were lost on European settlers, who were oblivious to the specially-adapted species until the Lewis and Clark expedition of 1806. The settlers were obsessed with raising livestock, which became a lucrative business once the railroads were established in the late 1800s. At first, coexistence was possible; after all, the semi-arid plains of Wyoming and Montana were not particularly attractive places to raise a family. But livestock-raising quickly turned into an industry, and the two were set on a collision course that would become contentious in 2005. Conservation groups noted a steep decline in Sage Grouse numbers in that era, resulting in a petition to force federal and state governments to take protective action.

After studying the maps in field guides and in eBird, I settled on the headwaters of the North Platte River, in north-central Colorado. One of the premier Sage Grouse locations is the expansive Arapaho National Wildlife Refuge near the town of Walden. Tourism is important but not a dominant economic force in this remote region of large flat sagebrush-grass flats ringed by three towering mountain ranges, which feed snowmelt into the meandering streambeds that feed ponds and eventually merge into the river. The Arapaho, nicely named after one of the tribes of the region, was established in the mid 1960s. The main purpose was habitat for nesting and migrating ducks and geese, who were losing ground to agriculture in the Midwest. An incidental benefit was the preservation of Big Sagebrush and the aptly-named Sagebrush Steppe habitat. This is yet another example of how habitat preservation for one group of species brings benefits to many more, a not-so-subtle feature of public lands management that is quickly forgotten in every case of proposed new refuge or park establishment. 

Sunrise at Arapaho National Wildlife Refuge. In the morning haze of distant forest fire smoke.

We began our refuge tour at sunrise, noting a great many perched Swainson’s Hawks waiting for warm air to soar in. Brewer’s and Vesper Sparrows were camped out with Sage Thrashers at the top of almost every sagebrush. A thrilling Long-tailed Weasel bounced along just off the road, looking for breakfast in the fields of White-tailed Prairie Dogs, which scampered across the road at every bend. American White Pelicans paddled around improbably in the ponds, a Sora sounded off, and American Coots were too numerous to count. Every large puddle held a few Wilson’s Phalaropes gathering insects on the surface. White-faced Ibis floated over in formation.

Swainson's Hawks near Coalmont, Colorado. Juveniles waiting for the next feeding.

Our first Sage Grouse appeared in sage and tall grass off the refuge road in the dim early light. They were unexpectedly large for grouse, much more so than the Dusky Grouse to which I was accustomed from New Mexico. They seemed weirdly huge, as if they had stretched beyond their prescribed body contours. Initially at rest, they perked up when I stopped the car, and mildly alarmed, soon wandered off into the sage. The light was challenging because the skies were filled with smoke from distant forest fires to the north and west in other parts of the continent. But we could make out the fine white markings on the back, a black belly, and long tail. A disjunct population of these birds occurs further to the south in Colorado and to a limited extent in eastern Utah. Having no contact with the rest of the species for probably millennia, it was declared a separate species a few decades ago, the Gunnison Sage-grouse. In the Arapaho, the new name is Greater Sage-grouse. Greater indeed, for these birds seemed to stalk off with aplomb. They melted quietly into sagebrush and out of sight.

White-tailed Prairie Dog, Arapaho National Wildlife Refuge

Oddly enough, these birds were not far from a herd of cattle. The refuge permits livestock in small numbers, reportedly to shake up the vegetation a bit and promote the growth of young sagebrush. Not being a big fan of arid-lands grazing, I was skeptical, but I must say that judging by the vegetation, the grazing is light indeed. Maybe someday the cows can be replaced by American Bison.

Cattle herd in the Arapaho National Wildlife Refuge. Notice the relatively healthy sage and grass: the grazing intensity is light here.

Later that morning we found a trio of Greater Sage-grouse in the area around Coalmont. They first appeared sitting in the middle of the gravel road, apparently taking in some sunshine in the cool morning air of about 6 degrees C. As we approached, they lost patience and took to the air. They flew strongly and with purpose on large wings, a few feet off the ground, and slowly dropped over the horizon. We found a large group farther down the road near a lake. Two adult females were chaperoning 6 young birds. We stayed silent and got close looks in the tall grass, before they slowly wandered off and disappeared. It was a perfect illustration of their need for luxuriant grasses. Although it appeared to be private land here, both sage and grasses looked healthy. Several Pronghorn wandered around as well, trotting through the sage with a supreme ease.

Greater Sage-grouse near Coalmont, Colorado

In the 1990s, wildlife observers and biologists became worried about a decline in Sage Grouse numbers, and a shrinking of the range. The causes were documented well by researchers. Habitat alteration by residential and commercial development and by a growing number of oil and gas wells were contributors. Fences and poles provide perches for predators that enhance their success at grouse capture. The intrusion of exotic plants is another factor. Livestock grazing, prompted by a growing national demand for MacDonald’s cheeseburgers, has also been mentioned. Many ranchers protested the analysis. Cows eat grass and Sage Grouse eat sage, so what’s the problem?

The impacts are many. Livestock can trample the sage shrubs as they forage, threatening the health of the plants. Heavy grazing causes the grasses to decline and even be eliminated. That leaves Sage Grouse chicks easy to spot by predators, causing a dent in nest productivity (the number of chicks fledged each year). The reduction of grasses alters the insect life, which adult and young grouse need for growth. Cow herds tend to bring in Cheatgrass (Bromus tectorum), an invading annual species from Asia that chokes out the natives. (I personally witnessed the dramatic growth of Cheatgrass in northern New Mexico in the 1990s and 2000s. The ground grows eerily green very early in the spring, and then quickly turns inedibly brown and shades out native perennial grasses that green up much later.) Incubating adults may abandon their nests when large herbivores come too close. Livestock are also devastating to fragile riparian areas that the grouse sometimes use for water and forage. Sagebrush can fall prey to ranchers who use heavy equipment to rip it out of grazing areas, in a desperate but usually fruitless attempt to increase the grass cover on the land. We saw a few areas like this in our drives around the area.

In theory, we have land managers who are federal employees and can watch out for these negative impacts on native wildlife, working in agencies such as the US Forest Service (USFS) and Bureau of Land Management (BLM). In practice, it is a different story. One of the conservation groups observed shrewdly, “the BLM is trapped by federal law, and compelled by politicians, local resource users, and its own organizational culture to continue livestock grazing even to the detriment of fish, wildlife and watersheds.” I have been known to cynically refer to BLM as the “Bureau of Livestock and Mining.”

In the face of this, conservation groups filed petitions in the 2000s to get the federal agencies to declare the grouse endangered. The US Fish and Wildlife Service (USFWS) agreed in 2010 that the bird should be classified as endangered, but that they lacked the money and staff to do so (the dreaded “warranted but precluded” designation). Conservation groups like the Center for Biological Diversity and the Western Watersheds Project kept the pressure on with negotiation and the threat of lawsuits. In 2015, it seemed like a victory for the conservationists was imminent.

It was not. Enter our beloved US Congressmen. They included language in appropriations bills in 2015 to prevent the USFWS from declaring the bird endangered. Now, this creates all kinds of confusion over the role of government agencies. The USFWS is ostensibly supported by Congress. Funds are allocated to them annually by Congress to carry out a prescribed mission. But now we have Congressmen dictating what actions they can and cannot perform? That seems blatantly contradictory. What is the use of having an agency to protect endangered species if Congress has its hand on the steering wheel? The USFWS, under pressure from western Congressmen, issued a statement in 2015 that they would rely on a land management plan as an alternative to Endangered Species Act listing. They trumpeted it as “an unprecedented conservation partnership” and claimed to be protecting 90% of the 173-million acre range of the bird.

Pronghorn near Coalmont, Colorado

Then Trump got elected, and things got worse, as you might guess. In 2018, Trump ordered political appointees (Ryan Zinke) to gut protections for the Sage Grouse, carving out nine million acres of land to wind and solar farms, drilling, mining, and cornfields for ethanol production. The recent Supreme Court decision on the Chevron doctrine (2024) is likely to complicate things even further. The rationale of the Congressmen (mostly western-state Congressmen) is that local authorities are already doing everything they can to protect habitat and ensure the grouse’s future. Is that true? The way to assess those programs is to look at numbers of birds detected in surveys, and those numbers continue to shrink.

Lark Bunting in Colorado

And that leaves us at a standstill. Both species of Sage-grouse are in a downward spiral, and both forms of government (state and federal) are standing around with their hands in their pockets. The likely outcome is that the birds will eventually become critically endangered. It might get to the point of no return, with no amount of money able to retrieve them. The bird with such a facility for vanishing into the tall grasses might end up vanishing into the aether instead.

Greater Sage-grouse, before disappearing into the tall grasses

We didn’t stay in the Walden area long enough to get an idea of how local people think about these issues. But one minor bit of insight comes from a roadside sign related to different wildlife issue. In November 2020, Colorado held a referendum on reintroducing wolves to the state, as a way to supplement the highly successful effort in Wyoming and its spillover effects in Montana, Idaho, and Washington. There was controversy over the proposal, and the vote was very close, but voters approved the proposition, and Coloradans are looking forward to hosting wild wolves for the first time in a century. In Walden, a landowner voiced his or her scorn over the reintroduction program with a prominent sign saying “If you voted for reintroduction of wolves, do not recreate here. You are not welcome.”

Roadside sign just north of Walden, Colorado

One would be hard-pressed to find a sadder manifestation of entrenched attitudes toward wildlife. Is this landowner really prepared to reject the revenue from wildlife tourism? In our short trip, we spent several hundred dollars to see Greater Sage-grouse, on rental car, gas, hotel bills, restaurant meals, and groceries. We participated in keeping Colorado businesses active and prosperous, just to see a rare resident bird. We plan to do so again in the future, since Greater Prairie Chicken and Sharp-tailed Grouse are still on the list. All of this provides a badly needed shot in the arm to Colorado’s economy. Doesn’t that count for something?

 

Variegated Fritillary. Near Zimmerman Lake, Colorado.

The Birds of Oppenheimer

 The Birds of Oppenheimer

Last year’s powerful film Oppenheimer moved people in many different ways and was granted many awards. Given my professional activities, my interest in the film embraces many dimensions. One worth capturing on this blog is the film’s depiction of the landscape and its wildlife, which was my preoccupation for three decades (still burning strong today).

The siting of the Manhattan Project at Los Alamos is a story documented by numerous historians and popular science writers, in greatest detail in “American Prometheus,” the fabulous book by Bird and Sherwin that inspired the movie. Oppenheimer had strong connections with northern New Mexico that trace back to his childhood. Although his professional life was centered at other places (Berkeley, Pasadena, Princeton, and Europe), he returned many times to vacation in New Mexico, ultimately purchasing a cabin there at the southern end of the Pecos Wilderness in the Sangre de Cristo Mountain range, east of Santa Fe. Today there are Forest Roads passing quite close to the cabin site; I went to that general area many times for hiking and wildlife watching, so I have a profound understanding of the allure. When Groves and Oppenheimer sought a site to build the bomb, they initially looked at picturesque Jemez Springs, northwest of Albuquerque in the southern part of the Jemez Mountains (American Prometheus p. 205). Groves didn’t think much of the canyon location, so Oppenheimer suggested the Pajarito Plateau, where he had taken long horseback rides on his visits. (Those rides must have begun in Santa Fe, not the inconveniently remote cabin location in the Sangre de Cristos.) The film depicts this search briefly but plausibly. Oppenheimer knew about the Los Alamos Ranch School on the plateau, and suggested that Groves consider it. (“Los Alamos” refers to the gallery forests of cottonwoods in the wet spots of the canyons.) Oppie would have known at that point that the view is inspirational and the mesa tops suitable for construction. The jeep ride from Jemez Springs to Los Alamos, along logging roads, must have been quite an adventure in the early 1940s, and would have taken easily a half day. But Groves was sold, and history was made. Hans Bethe and George Kistiakowsky were two of the legendary scientists on the project who appreciated the selection of that site, bringing back their own childhood memories of the Swiss alps, and they spent spare hours hiking up to the peaks above the project site. (My late professional colleague Tony Arrington was a graduate student of Kistiakowsky’s, who was raised in Kyiv Ukraine and then taught chemistry at Harvard.) They also carved ski trails out of the forested slopes – Kistiakowsky put leftover explosives to good use to bring down the bigger pine and Douglas Fir trees. (He needed practice on implosion design, after all.)

Gallina Canyon, Jemez Mountains. Ponderosa Pines that have escaped the axe. I don't know if Oppenheimer ever made it there, but it is the kind of place he talked about often.

The plateau where the Los Alamos laboratory is situated today did not get its name until quite late in the history of human settlement and use. The predecessors of today’s native American Northern Pueblos used the plateau about a thousand years ago (and likely much longer); ancient cliff dwellings can still be visited today in Bandelier National Monument, in Frijoles Canyon and other places. Early Spanish settlers left their mark in the 1600s-1700s; they carved wagon paths and brought livestock to graze, cut firewood, and expanded on the trails that the native Americans had left. Adolph Bandelier and Edgar Lee Hewett studied archeological sites on the plateau in the late 1800s. The story goes that Hewett thought the plateau needed a name. He must not have gotten input from the numerous Pueblo people who were close by, or maybe they did have names for it that Hewett chose to ignore.  But he landed on “Pajarito,” which means “little bird” in Spanish. I have wondered which little bird Hewett was inspired by. If he spent a lot of time there in July and August, he would certainly have seen four species of hummingbirds visiting the abundant penstemon wildflowers (Broad-tailed, Black-chinned, Rufous, and Calliope Hummingbirds). Or maybe he noticed the flocks of Bushtits using the Pinyon Pine and One-seed Juniper that were abundant on the mesa tops. Or the many Pygmy Nuthatches in the tall stands of Ponderosa Pine.

The southern tip of the Sangre de Cristo Mountains as seen from the Pajarito Plateau. At sunrise in December.

When it came time to film the 2023 movie, the director was faced with a problem of his own. The town and lab of Los Alamos are thoroughly developed, and the kinds of uncontaminated views that Oppenheimer appreciated no longer existed. So Christopher Nolan opted for Ghost Ranch, about an hour’s drive north of Los Alamos. It is a place of great beauty. With red rock cliffs looking over a wide valley, it is generally regarded as one of the most beautiful spots in the state, which Georgia O’Keeffe would reiterate. The iconic figure of Cerro Pedernal (“flint hill”) towers over the southern edge of the valley through which the Rio Chama meanders (or did, until Abiquiu Dam was so rudely imposed in 1959).

Cerro Pedernal looming above Ghost Ranch on a winter morning

Ownership of Ghost Ranch is a combination of private, US Forest Service, and Bureau of Land Management, preserving the kind of vistas that have provided backdrops for many films. The bird life of Ghost Ranch shares much in common with pre-development Los Alamos, making it a nice substitute, as you can experience today driving along Route 84. Like much of the land in the state, Ghost Ranch is both arid and overgrazed by cattle, which is a shame. But movie cameras don’t get close to the plants, so the defect is glossed over. A few other scenes capture Oppie moving with friends on horseback through the landscape, and these were mostly filmed in central Santa Fe county, where the Ortiz Mountains, Sandia Mountains, and Sangre de Cristo Mountains provide the backdrop. I know this because I recognize the peaks in the camera footage, and because the landscape is clearly pinyon-juniper (“P-J”) scattered among forbs. I spent many thousands of hours making my own bird-finding drives in that area along Rte 14, Rte 285, and the intervening dirt roads. (I carried out Breeding Bird Surveys for almost twenty years.)

Last week I watched Oppenheimer for a second time, so I could pay more attention to the details. It was a reminder for me of a dramatic device used by sound editors of Hollywood movies. When the action shifts from an indoor conversation to the outdoors, the sound editor sprinkles in a few bird sounds to cleverly clue in the audience. Listeners who are birders like me have this secondary auditory experience as we watch. It is mostly a pleasurable one, but with caveats. Hollywood sound editors don’t pay much attention to using the right bird sounds in the right locations. This is not just a minor issue for us; we spend huge amounts of effort searching for birds in local patches of suitable habitat at suitable seasons and time of day, so this stuff matters – a lot. Movie sound editors obviously choose bird sounds that are loud and distinctive to make an impression. That’s reasonable, but I wish they would try harder to get the right ones. So, specifically, “Oppenheimer” at about the 1:01 mark shows Oppie rolling into the lab site at Los Alamos to the call of a Cactus Wren. At the 1:27 mark, Kitty searches for Oppie on horseback in a dark, late afternoon canyon with snow patches on the ground, and a Carolina Wren sings out.

Cactus Wren, on a Cholla cactus near Blue Grama grass. Santa Fe county, NM

Those are North American birds, so what is there to complain about? Plenty. Cactus Wren is not a bird of the Pajarito Plateau. It is common in southern New Mexico, where the landscape is a lot lower, flatter, and more arid. Now to be sure, Cactus Wren is slowly on the march to the north. Most of us believe this can be attributed to overgrazing by cattle that has caused Cholla Cactus to move north and to colonize flat sunny spots where the competition from palatable grasses has been eliminated. Cactus Wren really likes Cholla, because it provides perfect sites for nest building, and it probably supplies the right kind of insect life for Cactus Wrens to thrive on. In recent decades, the northern extent of the range of Cactus Wren had been Socorro (Hubbard, John P. Check-list of the Birds of New Mexico. 1968), quite a ways south of the lab site that was being portrayed in the film. Those of us who bird in Santa Fe county got kind of excited when Cactus Wrens moved in and set up shop in 2014. Today, they seem to be entrenched there, at least in small numbers. But they are still restricted to places like the Caja del Rio plateau, across the Rio Grande and east of the Pajarito Plateau and significantly different because of the slope, predominant vegetation, and soil conditions. Cactus Wren was non-existent as far north as Los Alamos in the 1940s, decades before range expansion kicked in. So, sorry sound editor, but that particular bird call is incongruous in that setting.

How about Oppenheimer’s Carolina Wren? It is one of the loudest and most distinctive bird songs in North America, heard commonly because they are well adapted to human residences. But, as the name suggests, it is a bird of eastern North America, not New Mexico. West of the Mississippi, the wren family is represented more by Bewick’s Wren, Canyon Wren, Rock Wren, Cactus Wren, House Wren, and Marsh Wren. Here again, it is important to point out that Carolina Wren is slowly expanding westward. Nobody is quite sure why this is happening, because the North American west was never thought to provide the right habitat. Perhaps it is growth of human settlements. So Carolina Wren started to gain a foothold in New Mexico near Socorro on the Rio Grande, in dense riparian areas, in the late 1990s. I found one in Santa Fe county in the autumn of 2016, but it was a brief visit only. In the 1940s on Pajarito Plateau? Certainly not, as attested by published sources on bird distribution. (The most recent and most detailed of these is the treatise by ornithologist Sandy Williams.)

Carolina Wren. A rare vagrant at the Santa Fe Canyon Preserve, 2016.

The service provided by film sound editors is a vital one. I think it is wonderful when a film is enhanced by the right bird vocalization in the time and place of the film script. It adds an element of authenticity and realism. But, jeez guys, get it right. Bird songs and calls can only very rarely be captured by the microphone in the filming process, so they are almost always added in at post-production. Today we have voluminous sound libraries  that are available  at everyone’s fingertips – let’s use them! In the case of “Oppenheimer”, instead of piping in a Cactus Wren, it would have been great to use sounds of Pinyon Jay, Acorn Woodpecker, Northern Flicker, Western Wood-Pewee, Ash-throated Flycatcher, Plumbeous Vireo, Steller’s Jay, Juniper Titmouse, Black-headed Grosbeak, Bullock’s Oriole, White-crowned Sparrow – so many to choose from. Instead of the ringing song of Carolina Wren, it was a missed opportunity to use Canyon Wren, one of the most beautiful North American bird songs. They are commonly heard today in Los Alamos Canyon, above the town. Or how about a Grace’s Warbler?

Canyon Wren. Diablo Canyon, Santa Fe county, New Mexico

I make the same plea to Ken Burns, who has created so many wonderful films about American history. Burns’s editorial team makes frequent use of bird sounds, adding much to the film experience. But there are too many times when they choose a jay, oriole, sparrow, or warbler from the wrong side of the continent or the wrong elevational range or the wrong season. Surprising, in light of Burns’s exceptional focus on accuracy.

In years of watching films and television documentaries, I have found it amusing to note what bird sounds are selected to populate the soundtracks. One common call is the Boreal Owl. Ironically, Boreal Owl is one of the most difficult species to find in North America, at least when it is singing, which happens only when the snow is too deep for humans on foot. Not so rare in movies. Prairie Warbler is a frequent guest on programs, often mislocated in western places where it doesn’t occur. The fierce call of the Red-tailed Hawk is frequently heard on television ads. It is a piercing, descending scream. Amusingly, though, it usually accompanies the video image of Bald Eagle. Apparently, Madison Avenue thinks that the very different, whimpering call of the eagle is not what it should be, if you aim to sell stuff. British period dramas are fond of using the repetitive call of the Chiffchaff and the low hoot of the Eurasian Collared Dove. For Africa, the favorite seems to be White-browed Coucal, which I have nicknamed the “David Attenborough Bird.”

Red-tailed Hawk, Jemez Mountains, New Mexico

One additional comment about Oppenheimer pertains to the weather. The Trinity Test, the first explosion test of the newly designed bomb, occupies much of the middle part of the movie. The scene depicts a long delay in the test, at today’s White Sands Missile Range, due to a rainstorm. The portrayed project scientists and technicians don thick rubber raincoats or huddle indoors in a fierce, wind-driven rain. It appears to last for hours, causing everyone to mill about in nervous anticipation. In New Mexico, in mid-July?  Wait a minute. It doesn’t rain like that in the southwest. July is the month of afternoon thunderstorms, and it rains alright, but in any one location, it never rains for more than about fifteen minutes. The rain can be intense, but brief. And on a hot summer day, it usually feels nice to let your clothes get a little wet. In my thousands of hours of bird finding in the southwest, I never took a raincoat with me. Historical accounts say that there was a storm delay on that famous day (or infamous, to some). It was highly unusual that there was storm activity in the early morning at 4:00. But it was only a short one, and the intensity of the storm was “hollywood-ized” in the film as a tension-building device for dramatic effect.

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There is a tragic side to the otherwise compelling story of the site selection of Los Alamos. While the Pajarito Plateau provided enough flat spaces for the bomb development work, the plateau was subdivided by canyons with small and slow-moving streams. The canyons became the inevitable repository of chemical waste from the handling of nuclear materials. In the desperate scramble of wartime, there was no time even to consider waste disposal. Later, in the 1950s and 1960s, national standards for waste treatment were lax because fate and transport of chemicals and radionuclides was not well understood. Technologies improved in the 1970s and later, reducing outflow to the canyons, but the damage was done, and the canyons accumulated legacy materials. Analytical chemistry technologies made enormous strides during that same time, enabling the precise determination of even the most trace radionuclide quantities in soil, vegetation, and rock, and there are multiple, well-documented contamination areas that are known today. A program  exists today to keep track of these legacy sites, but unfortunately there is no practical way to clean up all of them without destroying the canyons as ecologically important areas for wildlife and spring runoff management. Ironically, if Oppenheimer had less love for New Mexico’s topography and scenery, and Groves had chosen some flat, featureless area for the Manhattan Project, the chemical and radionuclide waste problems would be far less pressing today. But that’s not the way it worked out.