Okay, it is finally getting a bit warmer as we have had temperatures above 40. And we have returned to Daylight Saving Time, so there is more daylight into the evening. But since there is still snow on the ground, we need more signs of spring. This news about kestrels may help.
On the discouraging side, kestrels no longer breed on the Vineyard, even though they used to be a common species nesting in and around our fields. However, we still see some sporadically in the fall and spring migrations. This decline has been attributed to habitat loss due to development, modern farming with monocultures and no unused spaces, use of pesticides that kill their insect food, the prevalence of West Nile Virus, depredations by the now quite common Cooper’s hawk, and competition with starlings for nest sites.
On the encouraging side, there have been recent studies showing that kestrel populations are increasing in places where people are putting up nest boxes. Closest to home, a retired school teacher named Tom Sayers, working in Connecticut along the Connecticut River, has increased the kestrel population from a couple of pairs five years ago to 31 breeding pairs in 2014, all nesting in boxes he put up and monitors.
His kestrels nest in boxes in fields that are at least 20 acres. They use boxes in farm fields that still have some small areas of diverse native plants; these microhabitats are where kestrels hunt because grasshoppers, dragonflies and other insects are still abundant there. The boxes he puts up that remain unoccupied indicate that they do not nest in monoculture crop or pasture areas, probably because their food is scarce in those areas. Three pairs of kestrels nest in one field, with their nests about 300 yards apart; each pair forages on their own patch of diverse vegetation.
He has a problem with starlings usurping his nesting boxes. Kestrels will not displace a starling that is using a box, even though they are slightly larger than a starling. He recommends either removing either the starlings or the box if starlings are setting up shop on a box.
Mr. Sayers attempts to color band all the chicks nesting in these boxes. So far, 28 of the 102 kestrels he has banded have returned to nest in his boxes. While there is considerable mortality when these chicks leave the nest and learn to hunt, some of the kestrels must have dispersed to other areas. Since we are not far, as the kestrel flies, from his study area, we need to check the kestrels we look for these color bands.
This good news about kestrels came from a paper Mr. Sayers presented at the annual Massachusetts Audubon Society Birders Meeting on March 7. It was so nice to hear positive news for a change! Now is the time to get some nest boxes up in Vineyard meadows, so they are ready for use in the coming nesting season, beginning in May.
Bird Sightings
Penny Uhlendorf has updated the red-winged blackbirds that were at their feeder on March 2. There were at least two female red-winged blackbirds along with some adult males and some first winter males. On March 4 they also observed one male and three female brown-headed cowbirds. The spring northward migration has finally begun!
There are quite a few feeder reports this week. This is not surprising since most of the ground, and the food on it, is still buried under snow. On March 4, John and Jan Wightman had a brown thrasher, several towhees, and chipping sparrows visiting their Aquinnah feeder, along with all the usual feeder birds. Happy and Steve Spongberg observed a brown creeper close to one of the feeders on March 5. This species does not seem to come to the feeders themselves, but will accompany the woodland foraging flock when they visit. Hatsy Potter reports that she has a fox sparrow, male towhee and red-breasted nuthatch visiting her feeder.
Christy Edwards, Lori Callo, Tim Johnson and Steve Bernier have found three snowy owls at South Beach between March 7 and 9. One is definitely a male, which is almost pure white, a second is a darkly spotted and streaked female or immature, and the third is an intermediately streaked individual. Ms. Edwards has been seeing two of the three throughout the winter.
We have commented that the snowy and cold weather has stressed a lot of land birds these past two months, but what about waterbirds? Multiple observers have mentioned dead ducks washed up on various Island beaches, and our frozen ponds have multiple duck carcasses frozen into the ice. Scott Stephens and Penny Uhlendorf observed a live first year eider that came ashore to preen and rest just a few feet away from them on the beach at Pilot Hill Farm; such tameness is unusual and may reflect a weakened bird.
Is this mortality unusual, due to the severe winter? Or is it normal for the end of winter? Many of us have observed great black-backed gulls catching and killing ducks; perhaps the ice enables us to see the accumulating evidence of predation by these large gulls.
Finally, Hilary Blocksom reports that a brown bat dropped into her kitchen sink on March 8! This seems to be early and too cold for bats to be active, though it did get above freezing that afternoon. She suggests it may have been carried into her house on a wet log. Do not try to pick up any bat, even if you think it is dead; their teeth are very sharp and even a chilled bat can move more quickly than you might think. Instead, place a box or other container over the bat, then slide something under the box to contain the bat, and finally transport it to a safe place to release it. Ms. Blocksom released the bat into her barn.
There are lots of birds around, so please get out looking for them, and be sure to report your bird sightings to birds@mvgazette.com.
Robert Culbert leads guided birding tours and is an ecological consultant living in Vineyard Haven.
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