Common Grackles

This species is the largest member of the blackbird clan that regularly occurs in Massachusetts. Long-tailed and gregarious, grackles are hard to miss whenever they are present, as their feathers shine with iridescence and their piercing voices creak and whine across suburban Massachusetts. These adaptable birds can turn up in almost any habitat.

Identification

Grackles of both sexes are entirely shiny black, with patches of green and purple gloss. Their slightly-downcurved bills are long and dark, and their pale eyes stand out at quite some distance. The best field mark for separating grackles from other blackbirds and similar species like starlings is the tail. 

Grackles have long, wedge-shaped tails that are especially visible in flight. Grackles are also quite large, exceeding a foot in length from bill to tail.

Behavior

Common Grackles are gregarious and highly vocal birds. They can often be seen foraging on lawns or sitting on fences during spring and summer in suburban areas, uttering sharp chak notes or else singing their grating, rusty-hinge song. They also routinely inhabit shrubby areas and swamps.

In fall, grackles gather into large flocks before migration at communal roosts, some of which can be impressively massive (as many as one million birds!). Most grackles migrate a short distance south to pass the winter, but some few opt to brave the storms each year, often mixed with flocks of other blackbirds.

Grackles & Pools

In late spring and summer, owners of swimming pools are surprised to observe the large common grackle (a member of the blackbird family) repeatedly dropping small white sacs into their pools. Those sacs are the excreted waste of young grackles. The adults then dispose of the sacs in the nearest body of water (often a pool), in an effort to keep a clean nest.

There are no apparent health risks associated with the fecal sacs, but it is recommended that you dispose of them before entering the swimming pool.

The best way to discourage grackles from targeting your pool is to cover the pool with a lightweight cover that can be easily removed. The good news is that this behavior only lasts as long as young are in the nest, about 2½ weeks.

If nest sites are known, you can also try thinning the trees in the fall, after the birds have left, which may make it less attractive as nest sites the following spring.

Status

Though they remain common and widespread as breeders in the Bay State, Common Grackles are showing signs of a decline in abundance according to the USGS Breeding Bird Survey. 

Winter encounters with grackles occasionally spike in mild years but have been steadily trending downward over the past several years.