Birds : Nesting season
By E. Vernon Laux
Published: June 12, 2008
The month of June constantly surprises - even after the exciting migration of May with its nocturnal pulses of birds, some returning to the Island to breed, others bound for points further north and passing by in the night sky, accompanied by great numbers of sea birds moving along shorelines. It is surprising at how quickly the migration ends. Birds' arrival time at breeding areas is essentially like clockwork, honed by hundreds of years of migrating, with successful migrants passing on their genetic information to the next generation. Startling is the appearance of baby birds and the loud, defensive behavior of adult birds trying to protect them while they are extremely vulnerable.
Hard to miss around the Vineyard are the ospreys. The unofficial mascot of the Vineyard, these large, powerful fish eagles are exciting to watch. It is easy to become mesmerized watching one hunt along a shoreline. Seemingly gigantic birds, they often go into a hover, staring fiercely and intently into the waters below. Often starting into a dive, then aborting as the fish moves or visibility is compromised, the ospreys come around for another pass.
The older, more experienced the osprey, the better they are at fishing. At this time of year, one encounters adults with young in the nest. Watch and keep score as they plunge towards the water, throwing their talons out at the last moment both to break the impact and prepare to snatch some finny prey. Some never miss, like some sort of aerial fishing aces - top gun fishermen, if you will.
Cold wet weather that has occurred occasionally during the past couple of weeks makes things very difficult for adult birds trying to feed nestlings. The cold and the rain retard insect emergence and activity at a critical time for developing birds. Adults must provide the necessary protein to the nestlings and this is very difficult when this kind of weather occurs. The heat wave just visited upon us is good news for insect activity and the resident birds depending on this vital source of protein.
This time of year, for birds, is all about perpetuating species. Time is short, potential hazards are abundant and the weather can be devastating. Yet most birds manage to successfully navigate the perils of the breeding season quite well as the continued existence of our resident birds confirms. It appears that most land birds are having a good, as in productive, breeding season.
As with birds, butterflies, dragonflies, and all manner of winged things including man-made aircraft, the wonder of flight is fascinating. On the Vineyard, there has been an influx of people and not any wildly exciting bird news. Most interesting at this season is the behavior of common birds. With young to feed and defend in the nest, a patient and careful observer will find much of interest.
Watch carefully if you see any adult birds with a beak full of worms or insects. They are clearly headed to a nest full of hungry nestlings. If you know the location of the nest, even better, so you can take up a position far enough away to be of no concern to the adults.
Photo by Julian K. Robinson
Notice that after about every three or four feeding trips to the nest that the adult birds fly off with a little white thing in their beaks. Many land bird species have developed a technique for ridding waste that make diapers look antiquated. Bird nestlings dispose to their excrement in little fecal sacks. The waste is packaged in a little white balloon, if you will, that the adults efficiently remove.
The benefits are many. The young birds are not covered in their own droppings that would foul their emerging feathers. The location of the nest, through its smell to prospective predators, is kept to a minimum as the adults carry these fecal sacks a good distance away before dropping them, thereby helping to conceal a very active nest site with lots of activity. It is a neat solution to the problem of waste removal.
Larger birds, like red-tailed hawks and ospreys, have evolved a different but equally satisfactory solution to this problem. The young back up to the edge of the nest and fire away, out and over. This instinctive behavior, genetically passed on, is important. Keeping feathers clean and oiled is critically important for birds that are dependent on feathers for flight, protection from the elements, and insulation.
Perhaps the most beautiful bird in the world, certainly one of North America's finest looking, the cedar waxwing, has been making its presence known for several weeks. These sleek and elegantly marked birds have been all over the Island. Reports from observers have ranged from mildly excited to over-the-top, "I can't believe my eyes," in the past few weeks. All observers have been delighted to see these marvelous birds. If one can detect this species' thin, high notes, you will start hearing them daily.
If you find a baby bird, the best bet is to leave it alone and remove any cats that are nearby. The adults know where it is and they locate each other through call notes.
Until next week - keep your eyes to the sky.
