The many shades of the warblers of May
May is a month of intense and concentrated bird migration. Unlike fall, when legions of younger birds take their sweet time heading south over a period of several months, spring migration is short and serious – taking too long could mean you don’t get to breed this year. For birders on the Cape and Islands, where so many species are just transients, this creates a similar urgency - to see these birds before the end of the month, when they, like the Celtics’ championship hopes, disappear.
For many birders May means one thing – warblers, those colorful little, caterpillar-consuming songsters. I am lucky enough to have a neighborhood the warblers seem to like – the developers didn’t clear-cut the lots like they do now, so the houses are nestled under an overstory of relatively mature oaks. And those oaks host lots and lots of little green caterpillars, which is exactly what a migrating warbler is looking for. For a week or so, I could walk out the door in the morning and hear 8 or 9 species of warbler, including sought after species like Tennessee, Bay-breasted, Chestnut-sided, and Blackburnian Warblers. As of yesterday, they are already gone - for most of these species my neighborhood oaks were just a brief but important refueling stop between Columbia and breeding grounds in the spruce belt of Canada.
Some warblers get a bit off course, of course, which keeps things interesting for us birder types. At the Mass Audubon Wellfleet Bay banding station, a drab, oddly flatheaded warbler ended up in the nets a couple of weeks ago. This bird, boring and brown to the birding philistines, was a rock star to my people – it was just the 5th record of Swainson’s Warbler for southeastern Massachusetts. This species breeds in lowland thickets from the Carolinas to East Texas, especially in stands of giant cane, a habitat all but gone now – seeing one of these birds anywhere is special, never mind this far out of range. Sadly for birders, it was never found again – these birds skulk among leaves in dense undergrowth, so if it’s not singing, good luck finding one.
It's not just about warblers in May – the shorebirds may not be as abundant as when they head south in late summer, but they are often in high breeding plumage at this time of year, which can be spectacular. But describing them quickly exhausts my vocabulary for “red-orange” – they are usually some combination of rusty, rufous, ruddy, tawny, and maybe even burnt sienna. Case in point the uber rare sandpiper seen last week in Eastham, the Curlew Sandpiper. This beautiful, ah, let’s say burnt orange sandpiper breeds in Siberia and winters in Africa and Australasia, so Nauset Marsh seems an unlikely place to find one. But there it was, nevertheless, along with hundreds of other migratory shorebirds bound for somewhere near the Arctic circle. Will it correct course and orient to Russia? Who knows – maybe it defected in support of Ukraine.
While many of the transient songbirds have moved through already, there is still time to wring the last few drops out of spring migration – some of the flycatchers haven’t even arrived yet, the shorebirds will be here another week or two, and undoubtedly more rarities will be turning up into June. So don’t put your binoculars in the drawer just yet – there are still great birds out there waiting to be found, and someone will have to decide if they are rusty or ruddy or russet or chestnut or auburn or bay or rufescent or cupreous or….