A Decline in Bird Habitats Concerns Experts
12/22/99
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RELAYED TEXT STARTS HERE:
Title: A decline in wildlife habitats causes concern
Source: Bergen Record Corp.
Status: Copyright 1999, contact source for permission to reprint
Date: December 22, 1999
Byline: Don Ecker
Of the more than 360 species of Neotropical migrant birds ranging
from herons and raptors to swallows and warblers, more than 130
species breed in New Jersey.
Nearly 80 of these are songbirds, many of which you may see in your
backyard during spring migration. Folks living near forest areas may
hear many different species in a chorus of song. These usually are
the males singing to defend their breeding territory from other males
and to attract females. Learning to identify birds from their calls
and/or song patterns is a fascinating part of bird-watching.
Neotropical migrants are birds of the Western Hemisphere that migrate
long distances from wintering grounds in the New World Tropics
(Neotropics) to breeding grounds in North America. The Neotropics
essentially consist of the tropical regions of Mexico and Central and
South America, south of the Tropic of Cancer.
During the past 20 to 30 years, biologists have been documenting the
alarming decline of many Neotropical migrant bird populations.
Habitat loss and fragmentation, caused by development and other human
activities, are the main causes of population decline.
Declines of forest birds of the Northeast are the best documented.
Unfortunately, many other groups of species such as mammals,
reptiles, amphibians, and invertebrates have suffered population
declines, and for similar reasons.
The Landscape Project for Rare Species Protection, a method to help
stem the decline of wildlife populations in New Jersey, began in
1994. Its mission, to document the distribution and abundance of
wildlife populations in New Jersey, identify the critical habitats
that these populations rely on, produce mapping showing these
critical habitats, and work cooperatively with landowners, county and
municipal planners, state regulators, land managers, and the public
to protect these important habitats.
As part of the project protection efforts, Endangered and Non Game
Species Program (ENSP) biologists started systematic surveys in 1994
documenting statewide distribution and abundance of bird populations.
As of this fall, the ENSP has completed bird and habitat surveys in
three study areas: the Delaware Bay, Highlands, and Pinelands
Landscapes.
Many species of Neotropical migrant birds tend to be more vulnerable
to habitat loss and fragmentation than birds that are resident or
those that migrate only short distances within North America.
During the past 30 years, extensive research in North American
breeding areas, particularly in northeastern forests, has clarified
the major factors that make Neotropical migrants vulnerable to
population declines. Many species require particular habitat types
for breeding (i.e. habitat specialists), and may require large tracts
of habitat for successful breeding, or share both of these
characteristics.
With less suitable habitat available, threats to adult birds and
their young increase. Mammals and bird predators such as brown-headed
cowbirds, tend to be more abundant in fragmented landscapes. In
addition, tower strikes during migration and attacks by free-ranging
house cats have been estimated to kill tens of millions of birds each
year.
Migration itself is hazardous: Bad weather, predators, radio towers,
and tall buildings with reflective glass claim large numbers of birds
each year. Migrating birds require quality habitats along migration
routes to rest, replenish fat reserves, and escape predators.
The loss of migration habitat reduces chances for survival. Often,
migrants have little time in which to breed, generally late April to
mid-June. Many have only one chance at successfully fledging young.
If the first nest is destroyed or preyed upon, a second nesting
attempt has a much lower probability of success.
There are things we can do to help:
Create or enhance backyard habitat. Find out how to prevent birds
from accidentally striking your windows.
Read about the impacts of free-ranging house cats on bird and small
mammal populations.
Become active in your community to conserve open space for wildlife
and people.