Oooh, goodie, fall migration has really started! I had an inkling that migratory movement was afoot when I received a call from Laurie Reese of Abel’s Hill. She reported two yellow warblers and two ovenbirds feeding in a mini flock in her yard on August 6. Then, on August 12, Ken Magnuson photographed an immature male redstart by his feeders at the Edgartown Golf Club. Then the icing on the cake . . . Rob Culbert found two female Wilson’s warblers and three bobolinks at the Farm Institute on August 10. Passerine migration has started with the presence of these warblers and bobolinks.
On the flats of the ponds, bays and harbors the Vineyard is hosting other types of migrants. Pete Gilmore found stilt sandpipers and white-rumped sandpipers at the land bank’s Sepiessa property on August 8. Lanny McDowell found two stilt sandpipers and a single white-rumped sandpiper at Sepiessa on August 11. Laughing gull numbers are up. Lanny McDowell escorted me, Barbara Pesch and Andrea Hartman to Norton Point on August 7 where we counted eight laughing gulls and two black terns. At Quansoo on August 8 Flip Harrington, Pete Gilmore, Warren Woessner, Lanny McDowell and I counted two Forster’s terns, three black terns and 116 semipalmated plovers! Warren Woessner found an American golden plover at Herring Creek Farm on August 3. Bill Lee, Warren and I saw the American golden plover again on August 10. Dale Carter spotted an adult little blue heron in the marshes next to the Dyke Bridge on Chappaquiddick on August 9. Raptors are moving as well. Tim Simmons spotted an American kestrel at the Manuel Correllus State Forest on August 7.
So it seems that the food availability might be diminishing in the north where these migratory species were nesting, plus the days are becoming shorter and colder. If there is less daylight it is more difficult to obtain the amount of food necessary for survival. The cold may result in the death of the insect population that certain species of birds rely on to exist.
It is interesting to note that prior to migration birds undergo a change in metabolism and begin to accumulate large amounts of fat. This fat essentially is the fuel needed for their long migratory flights. It is burned up during their southerly relocation. The birds that are arriving on the Vineyard now are feeding up and accumulating this needed fuel. It seems I accumulate this same fat and, although I “migrate” to warmer climates in the winter, I don’t seem to lose that fat. I guess I will just have to grow wings!
When visiting the tropics, I have discovered that there are smaller clutches of eggs, there is more predation and for some reason the tropical birds take longer lapses between broods than the same species that nest here and points north. So wouldn’t you find a nice place to stay warm and eat heartily during the winter and then return north where there is less predation, good food and a chance for multiple broods? Migration is a complex issue and is continually studied by ornithologists worldwide. There is new information annually on the cause for this massive movement. It is great fun for birders to see what arrives on the Vineyard during this southward fall migration, so get out and find a rare one!
Lanny McDowell found and photographed a family of Eastern screech owlets by his Tashmoo home. They were all shades of gray. Eastern screech owls come in two color morphs — rufous and gray. The question Lanny posed is: Are all Eastern screech owlets born gray and then they molt into rufous or gray? Later in the day Lanny returned to the site and found an adult rufous Eastern screech owl near the owlets. I went online and found the following information on the Cornell Laboratory of Ornithology site: “Red and gray individuals occur across the range of the Eastern Screech-Owl, with about one-third of all individuals being red. Rufous owls are more common in the East, with fewer than 15 per cent red at the western edge of the range. ... Intermediate brownish individuals also occur in most populations.” That did not exactly answer the question, but my gut feeling is they start gray and then molt into one morph or another as adults. I checked with Gus Ben David and he told me to tell Lanny to keep checking on the color of the young owlets. Gus said that undoubtedly before the owlets fledge they will have shed their gray down feathers and grown red feathers. Gus and I cannot ever remember seeing a gray morph Eastern screech owl on the Vineyard, but who knows, one of the Tashmoo owlets might be a gray morph.
The Chilmark Community Center group and I went to Sepiessa on August 12. We found a Cooper’s hawk and turkey vultures in the woodland. Along the sandy shore were many semipalmated plovers and two black-bellied plovers. On the mud flats two white-rumped sandpipers were feeding amongst several semipalmated sandpipers and one least sandpiper. A single bird landed near the white-rumped sandpipers. I looked at it briefly, thinking after showing everyone the white-rumped sandpiper I could review and show people what I quickly called a short-billed dowitcher. We never found the bird again and did not see it fly. Unfortunately, this bird could have been a stilt sandpiper . . . we will never know! I will be leading another bird walk from the Chilmark Community Center on Tuesday, August 19, at 8 a.m.
Least terns are confusing our local birders. In some areas there are only very few, if any, remaining at Norton Point and Quansoo. In other areas the least terns are still around and displaying courtship rituals. Luanne Johnson from Biodiversity Works mentioned that the least terns “have been going gangbusters at two of our sites. Some are still incubating late clutches — so we will see how they do. It certainly IS getting late.”