Date: 04/02/09
Contact: C. Douglas Nielsen
Phone: (702) 486-5127, ext. 3500

WHEN BIRDS ATTACK

Unsuspecting urbanites may see some rather strange behavior from one particular bird species during the month of April and into early May. This behavior may have people asking what birds are dive-bombing and why they are “on the attack.” The perpetrator is usually the northern mockingbird, very common in southern Nevada.

The northern mockingbird lives throughout the United States and is a year-long resident in most of its range. Luckily or unluckily for us, depending on how one looks at it, these medium-sized song birds prefer to nest within human habitats. They build their nests in trees and shrubs surrounding buildings, very often where grass lawns exist. The birds use dead twigs and stems for building materials and line their nests with grasses. It’s easy to identify a mockingbird nest because they generally appear to be sloppily-built.

“The birds don’t need an artistically designed nest, as they usually locate them in protected shrubbery,” said Cris Tomlinson, supervisory diversity biologist with the Nevada Department of Wildlife.

Mockingbirds are brownish-gray, about nine inches long, with distinguishing white patches on their wings that are easily seen while the bird is in flight. A long, twitching tail helps in the identification process; however, it is difficult to distinguish males from females. And during the nesting season both sexes share aggressive parental behavior.

Another characteristic that makes it relatively easy to identify the mockingbird is their singing. Although they can mimic the calls of many different birds, the song often heard around egg-laying time is a loud, repetitive scolding sound. Prior to nesting, the males can be heard singing a pleasant territorial tune in an effort to attract a mate.

In early April, mockingbirds pair up and build nests. About two weeks later they lay their eggs and become very protective of the nest. When the eggs hatch 10 to 14 days later, overprotective parenting can be witnessed at its best. Both adults will aggressively defend the nest and chicks from intruders, by scolding, chasing, and dive-bombing other animals and even humans. The behavior is referred to as mobbing, which means repeated harassment of the trespasser. What can be done to fend off an attack? Nothing, really, since mockingbirds are protected by the Migratory Bird Treaty Act. That means no harm can be done to these birds. They can, however, be discouraged from getting too close.

Tomlinson advised, “Mostly, we have to exercise patience. The chicks will be out of the nests within 12 to 14 days after hatching and the aggressive parental behavior will subside. If we can put up with the month-long madness we can enjoy the beautiful and varied repertoire of mockingbird songs throughout the rest of the year.”

The Nevada Department of Wildlife (NDOW) protects, restores and manages fish and wildlife, promotes fishing, hunting, and boating safety. NDOW’s wildlife and habitat conservation efforts are primarily funded by sportsmen’s license and conservation fees and a Federal surcharge on hunting and fishing gear. Support wildlife and habitat conservation in Nevada by purchasing a hunting, fishing, or combination license. For more information, visit www.ndow.org.