Rural Chatter: Birds, Nature and Environment: May 2012

Monday, May 7, 2012

Great-tailed Grackle - Quiscalus mexicanus

These grackles have moved to the United States from Mexico. Their range is the southern states from California to Florida, however, they are slowly moving more to the north. They prefer areas with a source of water and trees to nest in such as agricultural areas, mangrove areas and urban or suburban areas. They may migrate for the winter from northern areas, but are permanent residents in southern areas.

The Great-tailed Grackle, or Mexican Grackle, was historically almost exclusively found in Central and South America, but human alteration of the environment has caused the birds to expand their range to include parts of the United States. Their current range in the United States is north to eastern Oregon, with individuals sighted as far north as Canada, south to northwest Peru, and northwest Venezuela in the south; the grackle's range has been expanding north and west in recent years. It is common in Texas and Arizona in the southern regions and as far east as Western Arkansas.

Great-tailed and Boat-tailed species are primarily resident in their ranges, but have been undergoing dramatic

range expansion northward during the twentieth century. Populations of Boat-tailed and Great-tailed grackles in northern, recently-colonized areas, move southward during winter months. This animated chart shows this northern movement over the last 100 years:
http://birds.audubon.org/sites/default/files/photos/grackleanimatedmaps.gif

Our biggest grackle; this big, brash blackbird, the male Great-tailed Grackle shimmers in iridescent black and purple, and trails a tail that will make you look twice. The rich brown females are about half the male’s size. Flocks of these long-legged, social birds strut and hop on suburban lawns, golf courses, fields, and marshes in Texas, the Southwest, and southern Great Plains. In the evening, raucous flocks pack neighborhood trees, filling the sky with their amazing (some might say ear-splitting) voices.

This huge blackbird is hard to ignore due to its boisterous nature. Long, deeply keeled tail; large, thick bill, with nearly straight culmen; flat crown, shallow forehead and the adult male is entirely black with obvious violet-blue iridescence. Eyes yellow; bill and legs black. Adult female: smaller than male and doesn’t have the keeled tail. She is brown above with dull iridescence on wings and tail; buffy on head and below, becoming darker brown on belly and vent; eyes are yellow and the dark lateral throat stripes usually obvious. Immature male: smaller than the adult male, with shorter tail, dull iridescence, browner wings, and frequently dark eyes. Juvenile: like female, but paler and shows diffuse streaking below.

Great-tailed Grackles - females

Eight great-tailed grackle subspecies are recognized, but only 3 are found in North America. These northern subspecies are prosopidicola, found in the east of the great-tailed's range west to central Texas; monsoni, found from central Arizona east to western Texas; and nelsoni, found in California and western Arizona. All 3 subspecies of the great-tailed are spreading northward in the United States. For the most part, there is little information regarding which subspecies have spread to which areas; therefore the range descriptions given above are tentative. And some intergradation may be occurring now that these subspecies are coming widely into contact.

Bright yellow eyes
Iridescent black body, usually more blue-purple
Larger, longer tail; held in deep ‘V’ during display flights
Very large, long bill; nearly as long as head

Size & Shape

The Great-Tailed Grackle has a disproportionately
small, slightly rounded head on a neck that’s thin in relation to its large body. Males are long-legged, slender blackbirds with a somewhat flat-headed profile and stout, straight bills. The male’s tapered tail is nearly as long as its body and folds into a distinctive V or keel shape. Females are about half the size of males with long, slender tails.

Male

Length: 18.1 in
Wingspan: 22.8 in
Weight: 6.7 oz

Female

Length: 15 in
Wingspan: 18.9 in
Weight: 3.7 oz

Relative Size

Exceptionally long-tailed and large songbird. Much smaller by weight than an American Crow, but about the same length.

Color Pattern

Male Great-tailed Grackles are iridescent black with piercing yellow eyes, and black bills and legs.
Females are dark brown above, paler below, with a buff-colored throat and stripe above the eye.
Juveniles have the female’s dark brown plumage, with streaked under parts and a dark eye.

Great-tailed Grackles eat mostly various invertebrates, sometimes small fishes, frogs, tadpoles, snails, crayfish, lizards, small snakes, bird eggs and nestlings, also grain; forages on ground, mud flats, and in shallow water. It eats berries and larger fruits, newly planted and ripening grain, waste grain, seeds, fruits, berries, and nuts and larvae extracted from ground, ticks removed from cattle, various invertebrates and small vertebrates, carrion, offal; in fact these birds will forage nearly anywhere, from the ground, in shrubs and trees, and even by wading in shallow water. However, the majority of foraging is done on the ground.

Favored habitat includes partly open situations with scattered trees, cultivated lands, pastures, shores of watercourses, swamps, wet thickets, around human habitation, sometimes in marshes. Often roosts in village shade trees or urban parks. South America: common locally in mangroves and along shorelines and on lawns and in parks in towns and. Nests in trees, bushes, man-made structures, mostly near or over water; marsh vegetation where no trees or bushes are available near water. Sometimes nests in heron colony.

Short, but sweet little clip

Cool Facts

In winter, enormous flocks of both male and female Great-tailed Grackles gather in “roost trees.” These winter roosts can contain thousands of individuals, with flocks of up to half a million occurring in sugarcane fields in Texas’s Rio Grande Valley.
In 1900 the northern edge of the Great-tailed Grackle’s range barely reached southern Texas. Since the 1960s they’ve followed the spread of irrigated agriculture and urban development into the Great Plains and West, and today are one of North America’s fastest-expanding species.
The Great-tailed and Boat-tailed grackles have at times been considered the same species. Current thinking is that they are closely related, but different species. They do hybridize.
Because they’re smaller and require less food, female Great-tailed Grackle chicks are more likely than their brothers to survive to fledgling. Likewise, adult females may outlive males, resulting in a “sex-biased” population with greater numbers of females than males.
Although you’ll usually see them feeding on land, Great-tailed Grackles may also wade into the water to grab a frog or fish.
Great-tailed Grackles—especially females—learn to recognize individual researchers working in their breeding colonies, and will react with a chut alarm call when they see the researcher, even away from the nesting site.

According to Birdzilla.com, an unusual trick for a blackbird, the Great-tailed Grackle can plunge-dive to catch small fish in the same way terns are commonly seen foraging.

A fine little slideshow of several many photos of
the life of a Boat-tailed Grackle

Call

Low chut; males may give a louder clack. This bird has a large variety of raucous, cacophonous calls.
Song is a strange mix of slurred whistles and electrical static-type sounds, usually ending in a staccato, mechanical rattle; call is a soft tchut. The male Great-tailed Grackle's horribly loud "song" is a series of harsh rattles, squeaks like that of styrofoam rubbing together, whistles, sounds like the tuning of an old radio, and gravelly "Check!" calls. You can hear three here:
- One
- Two
- Three