Diversity

Diversity

When winter eases off and the ground starts to soften up, thoughts turn to a May ritual that I observe with friends. We appoint a day and time and pile into a car for a Big Day: a full day of searching for bird species – as many as we can find.  We sketch out a route, pray for good weather, look at the recent bird reports, combine it with our own intuition, and head out around midnight. A Big Day works on the constraint that everything you find must be within a single calendar day. The route is contained within the borders of one state.

Short-billed Dowitchers. Cedar Creek, Delaware, May

Scheduling a Big Day involves numerous tradeoffs. Obviously, it is important to exploit the stream of neotropical migrants that peaks in the spring, being on their way to northern breeding grounds, largely Canada. But spring migration is about a month long in most places – so which part of May? The answer lies with the lingering winter visitors. Many are long gone by the last day of April, but a few stay, and it’s important to capitalize on them. Try it too early to capture more of them, though, and you risk losing the late neotropical migrants, who are waiting for the increased insect life of the middle of May.

I have done Big Days in Vermont, Delaware, and New Mexico. The tradeoffs work out differently in each place, so it’s the first week of May in New Mexico, the second week in Delaware, and the third or fourth week in Vermont. I have also done a variant: a county Big Day, where you focus locally. My emphasis is Rio Arriba county in New Mexico, working from the Rio Grande up into the Jemez Mountains, spanning over 5000 feet of elevation. (From Black Phoebes to Gray Jays. I usually get stopped near the high point by a snowbank on the road – yes, even in the age of global warming.)

Northern Pygmy Owl. Jemez Mountains, New Mexico

The Big Day rules are goofy. Each year, I confess to having thoughts about why the heck we are doing it. Who cares how many species you get in just one day? The real enjoyment of spring migration is the sum of everything you experience in May. There are good days and slow days, so why obsess over a single day? Then there is the time you must take off work, the family obligations set aside (birthdays, Mother’s Day, stuff like that), garden chores abandoned. And then there is all the gas we burn to get around to as many spots as we can. There is the sleep deprivation caused by the brutal midnight-to-midnight regimen, which gets rougher as we age. And there is no substantive biological significance to such a tally – it doesn’t correspond to any developed protocol for a census.

Spotted Owls, Los Alamos, New Mexico

Our performance has been uneven, too. Sometimes things just don’t go your way. The enemy in New Mexico is wind, which can smother bird sound in the warm half of the day. Torrential rain has trashed attempts in Delaware. But the even more insidious problem is the fickle timing of migration, which operates in swells. If you happen to choose a lull, the morning can be a frustrating experience of non-birding.

Hepatic Tanager, Santa Fe county

The impulse to do a Big Day is a bit of an enigma. But I think I have the explanation: diversity.

This year, we got 21 species of warblers in Delaware – an astonishing demonstration of variety. The day also produced 11 species of sparrows (including the rare Nelson’s), 4 wrens, 5 terns, and 20 shorebirds. Vermont produced 21 warblers, both cuckoos, 11 hawks and falcons, 9 flycatchers, and 4 owls.

Chestnut-sided Warbler. Elmore, Vermont.

The lunacy of doing a Big Day stems from that subconscious impulse to celebrate the diversity in our midst. We need a reminder that the landscape has so much to offer, despite all the things going wrong in the world. Venturing out again to get glimpses of Blue-winged Warbler, Blackburnian Warbler, Louisiana Waterthrush, and Red Knot provides that multi-colored reminder and sonic wonder. There is, of course, the visual lightning bolt of seeing the first Scarlet Tanager of the year, sitting on a bare branch in the woods, the leaves only starting to emerge. But there is reassurance also in the timing: knowing that the first week of May brings Northern Waterthrushes to the creek in Galisteo. That the Varied Buntings return to sing in Walnut Canyon at Carlsbad, the Kentucky Warbler lights up the woods in Sussex County, the Woodcocks and Saw-whet Owls are once again calling in the boreal forests, right on schedule. Reaffirmation at its best.

Scarlet Tanager, Garrett County, Maryland

And for those who can’t put aside the numbers: Vermont 156. Delaware 177. And the glory day in New Mexico, in 2009: 202.