|The down of the common eider is prized for its softness and incredible insulating properties. This photo shows their extreme sexual dimorphism. The female in the foreground is subtly, cryptically marked, rendering her invisible under tundra vegetation while incubating eggs. The black-and-white males show up at a great distance, both to predators and to each other, which helps them defend a territory large enough to raise their young.
Mild winter continues
The past six weeks have been a big surprise to human observers and of great benefit to over-wintering birds and other wildlife. For gardeners, no butterfly bushes are dying due to extreme cold this winter. Contrast the date with a year ago and it seems as if the Island moved south 500 miles. Things have been so mild that some birds are as confused as this writer as to what it all means.
On Feb. 2, there were red-winged blackbirds singing at several widely separated Island locations, during the middle of the day. These hardy birds, amongst the earliest migrants, in fact they are almost always the first migrant land birds to arrive in noticeable northbound moving flocks in the spring, beginning in the third week of February, that at least on the Vineyard it is hard to know what is going on. Are these individuals that spent the winter and because of the temperatures have "morphed" out of winter hide-and-seek mode to breeders or did they arrive from the south already?
This winter had fair numbers of blackbirds that did not migrate south, gamely attempting to make it through what can be a really harsh time with no food and extreme temperatures. This is a big trade-off that has lots of consequences, either really good or really bad. The chance these birds took, the gamble, seems to have been a good call this winter. Saving all the time and effort necessary to migrate many hundreds, usually thousands of miles is a huge energy saver plus avoiding all the dangers associated with migration is also a big plus.
Another advantage for the birds, if the over-wintering birds are local breeders, is that it puts them in an ideal situation to obtain the best available habitat for breeding sites by being back on site to take possession first before returning migrants arrive back. They are already there and in the bird world, temporal ownership (which is all that exists) is 100 percent determined on a first-come, first-served basis. If they are birds that breed further north and the Vineyard was the southern terminus of their migration, then they are further north than others of their species and already closer to the breeding grounds than competitors.
Spring birds and global changes
Flocks of red-winged blackbirds were seen flying north at several places inland in Massachusetts, this past weekend. A few flocks were seen flying up the Connecticut River Valley in central Massachusetts and red-wings were reported singing at wetlands at many locations. This is most unusual and the birds are clearly responding to the mild temperatures, jumping the gun to begin these displays about a month earlier than is typical. But then, every year is different, and animals respond to conditions as they must. Is this response we are witnessing a temporary change in programming, or a true evolution of migratory and breeding strategies. "Adapt or perish" has never been a more apt description for birds due to the rapid environmental change that is occurring all over the globe, caused by a burgeoning human population. Few forms of higher life are able to adapt to such rapid, widespread biological change.
American robins have also been acting like winter is over. It is assumed, but not absolute, that most of the robins that winter on the Vineyard are enjoying the relatively benign conditions and abundant source of berries to eat compared to where they breed in Labrador, northern Quebec, Newfoundland or elsewhere. The Vineyard is the tropics for these birds and compared to what those places are like in the winter, it is.
It is known that robins move north from the Gulf Coast of North America almost exactly along with a temperature gradient that allows for earthworm and insect activity and exposed ground. This is the 36-degree Fahrenheit gradient and it seems to work very well. American robins are very hardy and widespread birds in North America that live in a great variety of habitats over a huge area. As a species they have adapted to a remarkable variety of conditions.
With the temperature being up and down and staying well above freezing for days, the "normal" winter patterns for birds have been changed as well. In has been a great winter for birds so far, in terms of available food resources and ambient temperatures. This means more birds will have survived the winter months to make it to spring and the breeding season. It is nature's way, whether we approve or not. The difference between this winter and a year ago seems almost impossible, yet it has happened and the plants and animals in the natural world must deal with it.
Lastly, the fantastic weather for beach walking has revealed a frenetic pace of courtship activity on the waters surrounding the Island. Virtually all the sea ducks are engaged in vivid displays and because of the calm conditions, walkers, birders, or anyone who cares to notice can hear the birds calling and displaying. The courtship displays of the various ducks - including common goldeneyes, red-breasted mergansers, surf scoters, and many other ducks - have been the best shows in town. It has been a treat to witness and because of the balmy conditions no obligatory freezing of body parts was required.
Until next week - keep your eyes to the sky.
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