Flora and Fauna News

Grackles Flocking for Night-time

By Michael Plagens
Sonoran Desert Sciences

PHOENIX, Az. ----- Great-tailed Grackles are now gathering together into great noisy flocks each evening as they prepare to roost for the night. They begin arriving up to an hour before sunset at preferred locations in groups of fifty to well over two hundred birds. After having lost and regrown there tail feathers a month ago, the males now sport a regalia of glossy black feathers and a huge tail. Females have a considerably smaller tail and are dark brown in color. Males and females seem to keep mostly segregated when sleeping or foraging. They forage a bit in the lawns or parking areas, get a drink from the irrigation system, and engage each other vocally.

The purpose of these flocks are two-fold. These are tropical birds that prefer to stay warm through the chilly desert nights. By selecting trees with a dense canopy of foliage and packing themselves close together they can maintain a comfortable microclimate. In addition there is safety in numbers. With a hundred pairs of eyes and ears it is difficult for a predator to sneak among them taking prey. If the birds all flush at once as if startled by a prowling animal, that animal will be confused if not frightened away by the sudden commotion.

Soon after dark the noisy chatter stops and the birds enter a slumber. Come early morning, at the first sign of light in the east, the crescendo of Grackle-chatter again begins to build. It's fun to imagine what is being communicated: Plans for the day? Wishes for good luck? Or just dominance rights proclaimed? With dawn the birds again gather in the lawn or parking area where they preen, stand in groups with each other, and taking turns strutting around. Finally they head out in smaller groups of 5 to 10 birds on their daily foraging activities.

Preferred trees to roost in are evergreen Ficus nitida and Eucalyptus. Huge flocks can also bring in other species of birds, namely European Starlings and House Sparrows; they all roost peacefully in the trees together. Several large flocking areas in central Phoenix:

If you know of other flock locations in Central Phoenix please report them!

Great-tailed Gracle (Male, with tail)
(Quiscalus mexicanus)