OUTDOOR BRIEFS

NORTHERN MOCKINGBIRDS

Visiting birds have aggressive nature

Unsuspecting urbanites may see some rather strange behavior from one particular bird species during 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.

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.

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.

NUISANCE SPECIES

Go fish, but don't move a mussel

Fisheries biologists with the Nevada Department of Wildlife are asking anglers to take the precautions necessary to prevent the spread of quagga mussels and other aquatic nuisance species between waterways.

"An aquatic nuisance species is any nonnative species of aquatic plants or animals that has a negative effect on desirable aquatic species or on the ecological conditions of our waters," said Jon Sjoberg, supervising fisheries biologist for NDOW.

A free ride on a recreational vessel is most likely the way quagga mussels were first transported from the Great Lakes region and introduced into the Lower Colorado River system. The mollusks were first discovered in Lake Mead in 2007 and subsequently have spread to waters in Arizona, California, Utah and Colorado.

To stop the spread of mussels and other nuisance species, boaters and anglers are encouraged to take a few minutes and clean their boats, trailers, canoes, waders, float tubes and other related gear before leaving one body of water and heading to another, regardless of their starting point or their final destination.

The rule of thumb for cleaning boats and other equipment can be summed as in three words -- clean, drain and dry. Clean the hull or trailer and remove all plant and animal materials. Drain any water from the boat, livewell and the lower unit as well as the boat trailer. And dry the vessel before moving elsewhere. If your boat has been in a body of water where quagga mussels, zebra mussels or New Zealand mudsnails have been found, keep the vessel dry and out of water for at least five days.

At first glance quagga, and zebra mussels, both native to the Dneiper River drainage of Ukraine, seem rather innocuous. But get enough of them in one place and they are a real problem. Both species can colonize in numbers large enough to block water intakes and even affect municipal, agricultural and industrial water supplies such as those used in power plants.