Cloudy With a 50% Chance of Warblers
We are a weather-obsessed people – talking about the weather, prognosticating about the weather, complaining about the weather - so I assume you have checked the forecast for the next few days. But have you checked the BirdCast? Yes, there is such a thing, and it’s provided by your friends at the Cornell Lab of Ornithology, as part of their quest to meet all of your birding needs. They are sort of becoming the Amazon.com of birding, but I digress.
BirdCast mines historical migration data and combines it with weather forecasts to make predictions about where migration will be happening on any given night. Think of the forecast as something like “cloudy with a 50% chance of warblers.” BirdCast also uses the US weather radar network to show real-time bird migration, because for as long as there has been radar we have known that it can pick up significant bird migrations. This was long a fringe sub-hobby within the birding community, where folks stared at hard-to-interpret Doppler radar readouts looking for mass bird migrations, but Cornell has made it easier to interpret with directional arrows clearly showing bird movements.
This is all very cool, of course, but here’s the thing – it doesn’t tend to work very well for Cape Cod, in my experience. Many a birder I know, including me, has headed out expectantly based on the BirdCast forecast only to be sorely disappointed by a bust of a morning. You’re better off just heading out whenever a cold front passes starting mid-late September. Cool weather tends to arrive from the north and west, which is also where the vast majority of the continent’s migratory birds come from, especially when you are on Cape Cod – there aren’t a hell of a lot of songbirds breeding to our immediate east. So when northwest winds drop the thermometer, get out there, because everything from hawks to warblers to seabirds could be on the move.
This week, some interesting migrants have turned up with the cooler weather, including a favorite of mine, the mysterious Connecticut Warbler, which birders noted in Mashpee and Truro. These boreal bog breeders winter in South America, where their small population disappears into the vast Amazonian forests. Since they breed and winter in low densities in remote areas, their ecology is still poorly understood, and they are famously hard to find in migration, when they tend to skulk in dense vegetation. Inexperienced birders invariably confuse them with Common Yellowthroats, Nashville Warblers, and other gray and yellow species, so photos are helpful in convincing others that you really saw one. Our window to see this species spans just a few weeks each year beginning in Mid-September, because in spring they follow the Mississippi valley back to Canada.
With a 7-month old baby at home, my field birding opportunities have been limited. Luckily, some migrants came to me this week, in the form of at least four warbler species that stopped by to use my bird baths. Warblers in migration typically don’t visit feeders, so having a bird bath in a small clearing surrounded by cover is the best way to lure them out of the trees where you can see them. Magnolia, Black-throated Green, and Blackpoll Warblers, plus a Northern Parula, all visited briefly for a bit of a splash between Sunday and Monday. There may have been others, but a naptime meltdown required my attention just as some of them showed up. This is the first time I can remember having multiple warbler species in my birdbath, so this was a treat even for this seasoned veteran birder. Presuming you don’t have a baby, I recommend getting out to seek fall migrants in places where forests, fields, and wetlands all come together, like Fort Hill in Eastham. Hopefully, I’ll see you out there. Well, one of these days, anyway.
This piece first aired in September, 2018.