When you smell saltwater on the East Coast, it’s time to look out for Boat-tailed Grackles. The glossy blue-black males are hard to miss as they haul their ridiculously long tails around or display from marsh grasses or telephone wires. The rich, dark-brown females are half the size of males and look almost like a different species. Boat-tailed Grackles take advantage of human activity along our increasingly developed coast, scavenging trash and hanging out in busy urban areas away from predators. This guy was photographed in Charleston on July 5th. Susanne and I both thought the female boat-tailed grackle nearby was a completely different species.
The Boat-tailed Grackle has an odd mating system, called “harem defense polygyny,” that has much in common with deer and other big game. Females cluster their nests in a small area safe from predators, and males compete to see which one gets to defend and mate with the entire colony. But it’s not as simple as it may seem: though a colony’s dominant male mates far more often with the females, DNA fingerprinting shows that only about a quarter of the young are actually his. The remainder are fathered by males who the females mate with while away from the colony. The oldest Boat-tailed Grackle on record was nearly 14 years old when it was caught and released by a South Carolina bird bander in 2003.
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