Florida Scrub-Jay: Aphelocoma coerulescens
Appearance:
The Florida scrub-jay is a 12-inch-long, blue and gray crestless
jay that lacks the white wing spots and tail feather tips of the
more common and widespread blue jay. A necklace of blue feathers
separates the whiter throat from the gray whitish forehead. The
tail is long and loose in appearance, and the back is gray.
Scrub-jays that are less than about 5 months old can be identified
by their dusky brown head and neck, but there are no such physical
traits that distinguish males from females.
Habitat:
Scrub-jays range over much of the western United States and
Mexico, but the physically and behaviorally unique Florida
scrub-jay is restricted to scattered, often small and isolated
patches of sand pine scrub, xeric oak scrub, and scrubby flatwoods
in peninsular Florida. They have very specific habitat
requirements. Scrub-jays prefer these various forms of scrub
habitat which burn frequently enough to maintain a tree height of
3-10 feet tall. They actively avoid other forest types, wetlands,
and large, open areas such as agricultural lands. While scrub-jays
can be found in areas where scrub has been recently converted to
other uses such as residential developments or farmland, their
survival and reproductive success are generally very poor in these
areas
Behavior:
Florida scrub-jays eat a variety of animal and plant items.
Insects comprise a major food source during spring and summer.
These birds also prey on other terrestrial invertebrates, and on
small vertebrates including frogs, toads, lizards, snakes, birds'
eggs, and even mice. Acorns are consumed year-round and are the
birds' staple diet, especially during the winter when drupes,
greenbrier berries, and tread-softly fruits are not available.
Florida scrub-jays mate for life. Breeding rarely occurs before
2 years of age, and often not until the birds are 3 or 4 years old.
Their breeding season is short compared with other Florida perching
birds; nests with eggs or young occur from early March through
June. Scrub-jays build a new nest each year. The nest, a shallow
basket of twigs lined with palmetto fibers, is typically built
about 3-10 feet above ground in one of the shrubby oaks. Scrub-jays
usually raise only one brood per year, but in case of nest
failures, they may lay two, three, or even four clutches a season,
each in a new nest. Clutch size is usually three or four eggs, but
may vary from two to five eggs. Incubation requires 17 days, and
the nestlings fledge about 17 days after hatching.
Florida scrub-jays live in family groups composed of a breeding
pair, their offspring from years past and present, and sometimes
even birds "adopted" from other families. In contrast to other
Florida songbirds, nonbreeding scrub-jays (especially males) may
remain in their parents' territory as helpers for several years
before dispersing to establish their own territory or join another
family. A well-defined hierarchy exists within these extended
family groups.
Cooperation among family members is a complex and fascinating
aspect of scrub-jay family life. Each family maintains a permanent
territory ranging from about 5 to 50 acres (averaging about 25
acres), which it defends from adjacent families. Scrub-jays exhibit
a well-established sentinel system in which each bird, in turn,
will watch for predators while other family members go about their
daily activities. The helpers assist in defending the breeding
territory, nest, and young from neighboring scrub-jays and
predators. They also help feed the nestlings and fledglings. They
do not, however, assist in nest-building, incubating, or brooding
activities. Long-term studies have established that helpers
contribute to the reproductive effort: Breeding pairs with helpers
successfully raise more young than do lone pairs.
The original range of the jay, estimated at 7,000 square miles,
has been reduced considerably by suburban development and
conversion of scrub habitats to agricultural uses. Many isolated
populations have been eliminated, and the historically almost
continuous population along the Atlantic coast has been radically
fragmented by urban development. Due to extensive habitat loss and
elimination of scrub-jays from much of their former range, they are
now legally protected as a Threatened Species by the United States
Fish and Wildlife Service and the Florida Fish and Wildlife
Conservation Commission. Preservation of existing populations is of
paramount importance, as is habitat management within designated
sanctuaries.
Habitat management for scrub-jays essentially consists of
periodically burning scrub tracts to maintain the desired shrub
height, canopy closure, and percentage of bare ground. Optimal fire
frequency for scrub-jay management is about once every 5 to 20
years. Mechanical site renovation may also prove satisfactory for
scrub-jay habit management where prescribed burning is
inadvisable.
Because of the territoriality of this species and the
requirement for maintaining specific habitat conditions, it is
unlikely that a "viable" population can be supported on any but the
very largest scrub preserves. It is likely, however, that even
small populations scattered throughout a region actually function
as a metapopulation, or "population of populations." It is
important, therefore, that scrub jays be preserved wherever they
occur, with each isolated population being recognized as an
integral part of a larger, regional scrub-jay population. As little
as 5-10 acres of suitable habitat may support a mated pair, but a
minimum of 25 acres per family is recommended as a general
guideline for establishing scrub-jay preserves.
Biologists in several regions of the state are currently
studying scrub-jays, both in undisturbed, natural habitats, and in
areas undergoing rapid development. Because it is often difficult
to determine a jay's sex or age in the field, marking each bird
being studied with a unique set of colored plastic and aluminum leg
bands is required. These banding techniques have been used on
scrub-jays for over 20 years, and do not harm or distress the birds
in any way.
By identifying families and individual birds, banding studies
provide information on territory size and stability, kinship of
birds within and between families, nesting success, survival and
dispersal of jays, and many other aspects of scrub-jays and their
environment. In many cases, interested citizens can assist the
biologists by reporting observations of banded birds to the
appropriate agency.
Predators are the number one cause of mortality for scrub-jays,
but disease also plays a role in scrub-jay population dynamics.
Translocation often is used as a conservation tool to boost
small populations or to move species back to places where they used
to live.
What You Can Do To Help:
- Support establishment of regional and local scrub-jay
preserves. Protection of scrub-jay populations on managed tracts of
optimal habitat is the best means of protecting this species.
- Provide habitat for scrub-jays. Plant, protect, and cultivate
patches of shrubby scrub live oak, Chapman's oak, myrtle oak, and
scrub oak on your property. Maintain all of your landscaping at a
maximum of 10 feet in height if you live on or near scrub-jay
habitat.
- Protect scrub-jays from your pets. Encourage passage and strict
enforcement of leash lows for cats and dogs in your community.
Protect areas being used by nesting scrub-jays from domestic
animals, especially cats.
- Restrict use of pesticides. Scrub-jays feed on insects usually
considered pests around golf courses and homes. Pesticides may
limit or contaminate food used by the jays. Reduce use of
pesticides if possible; if you must use them, please do so with
caution.
- Report malicious destruction or harassment of scrub-jays or
their nests. 888-404-FWCC (3922)
Additional Information:
Image Credit:
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