Fifteen or twenty years ago, few people in San Diego would have ever heard of a grackle unless they lived in Mexico, Central America or parts of the southeastern United States. The word itself causes people to think of evil trolls and dark magic, not a noisy black bird that some people would think as being evil, but others are fond of. Since the late 1990s, the shiny and showy “great-tailed grackle” has slowly taken over parks and public areas to become one of San Diego’s most common blackbirds. Studies show that these birds are quickly expanding north into northern California, Oregon, Idaho and Washington and they don’t seem to be slowing down.
Great-tailed grackles were originally more tropical birds residing mostly in desert and open areas of Mexico and Central America. Their strange clicks and sounds sound like they belong in a jungle and not a modern city. Their behavior is similar to crows and other blackbirds, including their intelligence, their aggression to other birds and their effect on agriculture. However, unlike crows, grackles are polygamous and communal nesters, with several females being seen using the same nest several times during the nesting season. Males watch over their females in a way similar to roosters watching over their hens.
Grackles have frequently been observed killing other birds, particular at feeders or in areas where they are feeding. Sparrows, doves, and killdeer are frequent victims in what seems to be unprovoked attacks by the medium-sized blackbird. The first two are often seen feeding with grackles, usually with no problem, when, suddenly, the grackle attacks and kills them. With killdeer, it is unknown what incites them to attack, but they have been observed chasing them into the water and pecking them to death. They sometimes eat the birds they kill and have been observed eating some sparrows and nestlings. Most of the time, their aggression rarely goes behind a few pecks and stomps by the grackle.
As the great-tailed grackle continues to move north, measures for their control and management will need to be planned to protect crops. Since it is a native bird that is expanding naturally, grackles are protected by various laws including the Migratory Bird Treaty Act. People who regularly feed backyard birds should prepare for their arrival and make plans to feed the grackles away from where their smaller birds feed. They also have some beneficial behavior such as eating disease-causing parasites off of cattle. Great-tailed grackles are very resourceful and hardy and will, most likely, continue their expansion to the north.