Sunday, March 24, 2013

Blackbird Fallout and a Rare Yellow-headed Visitor

Our blackbird flocks are composed mostly of Red-winged Blackbirds and Common Grackles

The weather has remained decidedly winter-like in the Northeast, and this is leading returning flocks of blackbirds to remain concentrated in good habitat areas throughout the region. Marshes can be especially good places to find these mixed flocks of Red-winged Blackbirds, Common Grackles and Cowbirds, but nature preserves like ours with bird-feeding stations can also become major blackbird havens.

The flocks very efficiently glean the ground around the bird feeders for edible morsels
At the nature preserve many hundreds of blackbirds have been descending on the bird feeders and to a large degree displacing our usual patrons – including the Cardinals, Mourning Doves and sparrows. The vast majority of the blackbird flock is composed of male Red-winged Blackbirds and that species’ boisterous calls contribute most to the incredible din that the flocks generate. Typically the male Red-wings come north before the females; they do this in order to make an early claim on the best breeding territories.
The blackbirds have somewhat displaced many of our other winter patrons
Blackbird flocks move with a good degree of synchronization, even though their flight formations tends to be looser then that of waxwings or starlings. The blackbird flocks fly low over terrain, and their large flocks can be extremely long – sometimes even stretching from horizon to horizon.
A male Red-winged Blackbird sits upright and starts to show his red wing feathers

Cowbirds make up a smaller proportion of our blackbird flocks
In the early morning, just after the sun rises, the flocks arrive at the preserve and land in the trees around the feeding stations. When all looks safe and secure on the ground, a few brave individuals fly down and start to feed. When it’s clear to all that these pioneers were not snapped up by monsters, the rest begin to descend – but only few dozen at a time, until the entire flock is down and feeding. A feeding flock is intensely skittish, and if any individual in their group gives the signal (which as far as I can determine, is imperceptible to an observer), the flock simultaneously takes flight with a percussive “whoosh” sound. After this they usually gather in the trees above the feeders again, but sometimes the flock will go further, and even leave the general area.
The Common Grackle has an iridescent blue and purple head - hard to see during a snow squall

Some Grackles have a taste for the suet
However, this never lasts long, and soon enough the flock is back in all its glory. The sound of many hundreds of blackbirds simultaneously calling is pretty overwhelming, and to me, it is the first true indication of spring. When there is a break in the weather and when the snow and ice melt on the breeding grounds, these large flocks will break up and the birds will begin staking their territorial claims. But if the winter weather makes a comeback, the flocks are quickly reconstituted and they return to the winter feeding areas. 

A male Yellow-headed Blackbird (a rarity for our region) probes with its bill into the seed husks
At my yard feeders last week we picked a rare visitor out of our own mixed blackbird flock. It was a male Yellow-headed Blackbird – a species that breeds in the far west and winters in Mexico and the extreme southwestern US. This species shows up in the Northeast only by accident. For us, the bird was easy to pick out of the moving flock. Its bright yellow hood and large white wing patch were very distinctive markings, but on the ground, among the throngs of mostly Grackles and Red-wings, the bird was surprisingly difficult to locate. This was due to its feeding behavior. When looking for seeds the Yellow-headed Blackbird would have its face pressed right to the ground – with its beak probing into the snow, and this effectively concealed its yellow front. Also, the bird’s white wing patch is not so evident when it’s not flying or displaying.
The Yellow-headed Blackbird - continuing to feed during an intense snow squall
When feeding the Yellow-headed Blackbird would usually hold its tail high, and at a noticeably more extreme angle than the Red-wings do. So in order to locate the bird, we would look for the one tail that was sticking almost straight up. The Yellow-headed Blackbird remained with us for 2 days, and then a short thaw prompted the flock to move on or disperse. In subsequent days, after winter had reasserted itself, the blackbird flock reassembled at the feeders, but this time there was no Yellow-head in their ranks. Hopefully, he has realized his mistake and is making his way back west.

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