Tag Archive | blackbirds

Wintering blackbirds in Texas

Winter leaps upon us in a flash. One minute, it seems, it is a very distant shape looming faintly on the horizon. Suddenly, before we know it, winter has struck, leaving us wondering where the summer went. In Texas, the same seems to happen with wintering birds. One day, only the year-round residents who call Texas home can be seen. The next day, countless wintering birds of all shapes and sizes are everywhere, confusing even the most attentive eye.

Countless blackbirds flock together during the winter

On a recent trip to Brazos Bend State Park here in Texas, about an hour southwest of Houston, we observed some spectacular flocking in action. Literally thousands upon thousands of blackbirds; Red-winged Blackbirds, Brown-headed Cowbirds, Common Grackles and European Starlings congregating on some farmer’s fields. They swarmed and swirled, seemingly in perfect coordination, lifting off and landing as a unit. And yet, this is not a sight you can readily behold on these bird wintering grounds. You don’t see flocks of thousands of these species doing this in the summer, so why do they do it in the winter???

These blackbirds have quite a few reasons for doing this in the winter but these flocking habits also have numerous downsides. First of all, on the positive side, foraging is greatly improved by the large flock as opposed to a single bird or a small group. The more eyes you have working together, the easier it is to find food! More eyes can also mean more safety from would-be predators, and trust me, there are a lot of them!

This brings us to one of the downsides of wintering flocks. Predators. Lots of them. Where there is food, there are consumers, waiting to, well, consume the food. Raptors see these blackbirds as one huge buffet just waiting to be sampled. In a small farmer’s field, we counted up to 20 raptors: about 10 Caracaras, many Red-tailed Hawks, several White-tailed Hawks, a Turkey Vulture and a couple of Northern Harriers, all exploring the delightful opportunity of a full stomach all winter long. If these hawks were to stick with the group of blackbirds, they could potentially always find one or two to pick off from the pack. The more birds in a flock, the more noise and commotion they make, rendering them easily visible targets.

Large concentrations of any living thing invariably bring with them two other depreciating factors; disease and competition. Avian diseases can be spread very quickly in such large flocks and may sometimes ravage a great portion of the local species. More birds might find better food sources but if there isn’t enough to go around, there simply isn’t enough. Weaker, slower and sick birds often will be the first to go hungry as they cannot compete with the healthier individuals.

It was definitely a neat sight to behold, especially when a raptor would plunge into the center of the throng, sending up explosions of blackbirds. One of the White-tailed Hawks that we spotted, an immature, had a very full crop (a muscular pouch near the throat used to store food), showing us that it had been eating well recently.

In the end, the advantages of these congregations greatly outweigh the disadvantages and it is a bewildering sight that will continue to captivate many a fortunate observer.

Posted by Matthew Sim

Bird Profile: Red-winged Blackbird

Up here in the northern part of the continent, we know when spring is here when the robins arrive. These are not the only harbingers of warmer days however; the Red-winged Blackbird heralds the arrival of spring as well, the males arriving before the females to claim their territory.

One of the most abundant and widespread birds in North America, the male is a striking bird; all-black plumage save for his bright red and yellow wing epaulets. The female is a heavily streaked brown bird with a light streak over the crown and above the eye. Males have harems of females living in their marshes, these harems can sometimes number up to 15, but up to one half of the nestlings turn out to be sired by a male other than the territorial bird. During the breeding season, Red-winged Blackbirds are rarely seen far from water and are communal nesters, often nesting alongside other species of blackbirds. Once nesting is over, the Red-winged Blackbird forms flocks and go out to forage over the countryside, returning to marshes to roost at night.

Red-winged blackbirds are a common victim of the parasitic Brown-headed Cowbird but this does not seem to affect the former`s numbers. The young are mostly fed insects, and this is exactly what the female Red-winged Blackbird pictured above is doing; she is feeding insects to a fledgling hidden in the grass. The male does a remarkable job and helps feed  the fledglings in is territory; there can be quite a few young birds to feed!

Red-winged Blackbirds may be seen at any marsh, lake or pond in Calgary with cattails and bulrushes. Don`t forget to listen; you can always tell if there is a Red-winged Blackbird nearby if you can hear the males distinctive “Conk-la-ree“ song.

Posted by Matthew Sim

Cowbird Catastrophe

The Brown-headed Cowbird has become a menace to songbird populations all over North America. A small, stocky blackbird, the males have glossy black plumage and a rich brown head whereas the females are drab brown birds. What makes the Brown-headed Cowbird such a menace to songbirds is the lazy manner in which they raise their young.  Females will use all their energy over the breeding season to produce eggs, sometimes up to 50 a summer. They lay these eggs in the nests of unwary birds; usually at the cost of the smaller bird’s young. The young cowbirds usually hatch earlier than their foster parents chicks and therefore, get most of the food, which can ultimately lead to the death of the foster parent’s young. The Brown-headed Cowbird parasitizes more than 200 species of birds; the Chipping Sparrow being one of the most hard hit species.

In the above photo, there are 4 male cowbirds all looking up from my bird feeder at the arrival of a juvenile Grackle.

There is a history behind the cowbird’s parasitism. At one time, it followed the buffalo herds across the prairies, a nomad, and therefore could not raise its young, resorting to the help of unwitting songbirds. Following herds of buffalo, the Brown-headed cowbird’s range was limited to plains and prairies. Deforestation and forest fragmentation by humans, however, opened up the way for the cowbird and they started to parasitize more and more species. Due to deforestation, the cowbird has expanded significantly, both in range and in number and it now poses a threat to some species.

Several species, such as the Yellow Warbler, have developed defences against cowbird parasitism and recognize the cowbird egg. The female Yellow Warbler will make a roof over all the eggs, including her own, upon recognizing the cowbird egg. She will then lay her eggs again. Other birds will throw it out of the nest or abandon the nest all together.

This one species goes to show how much human actions can change the world around us.

Posted by Matthew Sim

Backyard Birds: Common Grackle

The Common Grackle can be a handsome bird when seen from a short distance. Covering its head, neck and upper breast is a purple iridescence that can amaze viewers in the right light. The rest of its feathers, including its long, wedge-shaped tail, are glossed in a bronze-green sheen. But this beauty can be lost on many; a result of the combination of the grackle’s lack of table manners (and all other manners), its voice that sounds like “an un-oiled wheelbarrow” and the invasion of both lawn and feeders by large flocks of  these noisy birds.

Canada’s largest blackbird is both noisy and cocky, and is a resourceful forager. The grackle’s main summer diet consists of insects, small invertebrates and occasionally the eggs and nestlings of other birds. In winter, it will eat waste, grains, seeds, fruit and garbage. They will follow plows to catch invertebrates, pick leeches off the legs of turtles and steal worms from robins, among other techniques to get fast food. The grackle breeds in many different sites but it favours damp, open woodlands, the shores of lakes and streams and wet meadows. Be on the lookout for Grackles as they return to Alberta in April; they are almost here.

The young grackle is even noisier than the adult.

Note the long, wedge-shaped and keeled tail of this grackle.

 

Posted by Matthew Sim