The timing of bird migration is a tricky thing to predict. Over the past two weeks, I've seen a variety of migrants passing through the area – including some nice species in my yard. But reports of many species are still few and far between, and other species are absent altogether. It is still early for many species after all.
At the beginning of this week Kendra and I ventured to Crown Point to check out the bird banding station which will operate there through May 18th. When we arrived, the banders asked us if we had any birds in our pockets. They had caught only two birds first thing that morning. We stayed and chatted with the banders for a few hours, periodically checking the nets. But we caught no birds. Zero. Nada. And so we sat and discussed one bird related topic after another, including the slow start to the warbler migration.
There was a light south breeze and it seemed reasonable that warm southerly air and south breezes would theoretically drive the birds to the station from the south. But perhaps those same south winds are making it easy for the birds to shoot straight passed us and the station so they can establish territories up north. Ironically, south winds that bring birds north coupled with inclement, rainy weather locally can drop the birds out of the air – giving us a good fall out of species – and make Crown Point very active.
And the high pressure system that has been sitting on us for the past several days – and giving us beautiful weather is not forcing any birds down. More than that, it seems partly responsible for helping to block the birds from coming north at all.
Most of our migratory species come from the Neotropics and the Caribbean, and a larger view must be taken in order to understand their movements. I have unfortunately not been paying close attention to the weather in places such as the Gulf of Mexico – over which many of our species fly on their way here. Without favorable conditions, they generally won't attempt the crossing. After all, a head wind could doom them.
But I've seen reports from places like Texas and Florida of good migrant numbers of late (as there should be) – suggesting birds are on the move, but perhaps that the storms and rain that have been blanketing the south for days are trapping all the migrants there and not allowing them through. For instance, there was a recent report out of Texas that there was a great movement of warblers across the Gulf that ran headlong into a line of thunderstorms and north winds. The fall out of birds was evidently tremendous and many of the birds were looking exhausted having survived the Gulf crossing. Those birds would certainly need time to restock their energy before moving north. And others certainly would have perished.
All this seems to jive too as reports from elsewhere in the northeast consistently note few birds. For example, last weekend in Philly my brothers found very few migrants when they went out birding. It is difficult to say for certain, but the low pressure system down south with all of its rain and our high pressure system which has held serve up here for so long seem to have stalled things considerably.
And so this year our migration appears to be starting with a trickle, but as the weather shifts, the flood gates will open, and quickly. Even as I write this on my deck, I've heard warbling vireo, black and white warbler, black-throated green warbler, and Cape May warbler in my neighborhood – all firsts for the year. Couple those birds with a Lincoln's sparrow which has been in my yard for four days, and a merlin which would like to eat any of them, and you have the beginnings of a migration.
And so as the weather shifts later this week, birds will start showing up in good numbers. And many places – such as Crown Point – will be good places to check out the migration. The birds will come. After all birding teaches us nothing else if not to be patient.