Wednesday, October 26, 2011

Florida's Blue Backwoods Gem, The Florida Scrub Jay



The Florida scrub-jay (Aphelocoma coerulescens) is a 2.5 to 3-ounce, 12-inch-long, blue and gray crestless jay that is endemic to peninsular Florida’s xeric oak scrub and scrubby pine flatwoods. In fact, the Florida scrub-jay is the only bird species entirely restricted to the state of Florida. In the adult plumage, a necklace of blue feathers separates the whiter throat from the gray underparts, and a white superciliary line or eyebrow often blends into a whitish forehead. The back is gray and the tail is long and loose in appearance. Scrub-jays less than about 5 months of age can be identified by their dusky brown head and neck and shorter tail. However, in late summer and early fall, juvenile scrub-jays undergo a partial molt of body feathers that renders them indistinguishable from adults in the field. Adult male and female Florida scrub jays are not distinguishable by plumage, but are differentiated by a distinct "hiccup" call vocalized only by females.
Florida scrub-jays occupy year-round territories averaging 22 acres in size. This species is one of the few cooperative breeding birds in the United States, whereby surviving fledgling scrub-jays usually remain with the breeding pair in their natal territory as "helpers,” forming a closely-knit, cooperative family group. Group size ranges from 2 to 8 birds, but pre-breeding numbers are usually reduced to either a pair with no helpers or families of 3 or 4 individuals (a pair plus one or two helpers). Helpers participate in scanning for predators, territorial defense against neighboring scrub-jay groups, predator-mobbing, and the feeding of both nestlings and fledglings.
Because of their cooperative breeding strategy, Florida scrub-jays typically delay mating until at least 2 or 3 years of age. Nesting is quite synchronous, normally ranging from March 1 through June 31 and nests are usually placed in shrubby oaks, 1 to 2 meters in height. Scrub- jay clutches usually contain 3 or 4 eggs, are incubated for 17 to 18 days, and fledging occurs 16 to 19 days after hatching.
Fledglings remain dependent upon adults for food for up to 2 months after leaving the nest.
Florida scrub-jays usually live their entire lives within a short distance of where they were hatched. Usually, a male pairs with an unpaired female within a portion of his natal territory ("budding") or within a few territories of his natal territory. Young females typically disperse from their natal territories earlier than males and wander greater distances from home before pairing with a male. However, most Florida scrub-jays pair and become breeders within two territories of their natal ground; most dispersals are two miles or less, and in suitable habitat, more than 95 percent of all observed scrub-jay dispersals are 5 miles or less in distance.
Scrub-jay dispersal behavior is influenced by the intervening landscape. Protected scrub habitats will most effectively sustain Florida scrub-jay populations if they are interspersed within a matrix of surrounding habitats that can be utilized and traversed by scrub-jays. Brushy pastures, scrubby corridors along railway and country road right-of-ways, and open, burned pine flatwoods provide links for colonization among scrub-jay populations. However, expansive bodies of water, dense forest, urban development, suburban residential areas, shopping malls, major highways, and treeless, wide-open pastures inhibit dispersal movement of Florida scrub-jays.


Florida scrub-jays forage mostly on or near the ground, often along the edges of natural or Man-made openings. Animal food items consist primarily of terrestrial insects, but may include a wide array of species weighing up to 1/3 the body weight of a scrub-jay including, treefrogs, lizards, snakes, bird eggs and nestlings, and juvenile mice.
Acorns are extremely important in the diet of Florida scrub-jays, especially from September through March. During this time jays harvest and cache thousands of scrub oak acorns throughout their territory. Each scrub-jay may cache 6,000 to 8,000 acorns per year. Acorns are typically buried beneath the surface of the sand in openings in the scrub during fall, and retrieved and consumed in winter and early spring.
The Florida scrub-jay was first listed by the Florida Game and Fresh Water Fish Commission as a State-listed threatened species in 1975. The U. S. Fish and Wildlife Service (FWS) subsequently listed it as federally threatened pursuant to the Endangered Species Act in 1987. A 1993 statewide census documented about 4,000 breeding pairs of Florida scrub-jays remaining in Florida, including 374 pairs in mainland Brevard County. Coupled with the estimated 850 breeding pairs of scrub-jays on the Federal lands of Kennedy Space Center, Merritt Island National Wildlife Refuge, and Cape Canaveral Air Force Station, Brevard County’s 1993 Florida scrub-jay population was the highest of any county in the state. However, State-wide Florida scrub-jay population trends are closely correlated with scrub habitat loss and the 1993 population estimate of 4,000 breeding pairs was no more than 15% of the pre-settlement population estimate. In spite of legislated protection by the Endangered Species Act, the most precipitous Florida scrub-jay population decline has occurred during the last 15 to 20 years with an estimated 25 to 50 percent reduction in jay numbers. Recent studies in southern Brevard County have documented a decline in scrub-jay breeding pairs of more than 33 % since 1993.


Florida scrub-jay densities may increase in sparsely developed suburban areas where many patches of scrub remain and build out is 33 percent or less. These population increases in modified habitat probably result from supplemental food sources and the initial creation of openings in the scrub and visual buffers (buildings) to neighboring jay families. However, as development escalates toward complete build out, the survivorship of fledgling jays declines and failed nesting attempts increase. Because adult scrub-jays are long-lived, resident pairs often persist for years in some of the most densely human-populated Florida suburbs. Although these breeding pairs may continue to nest, they incur high nest failure rates and all suburban scrub-jay populations studied are declining. Annual nesting productivity must average at least 2.0 young fledged per pair for a population of scrub-jays to remain stable for the long-term.
Scrub Conservation and Development Plan (SCDP)
The Endangered Species Act protects endangered and threatened species from Federal and non-federal actions that result in the unauthorized "take" of individual protected animals or that may jeopardize the continued existence of a protected species. The FWS describes a take of protected species to include nests, eggs, young, adults, or habitat and is defined as harass, harm, pursue, hunt, shoot, wound, kill, trap, capture, or collect, or attempt to engage in any such conduct.
A 1982 amendment to the Endangered Species Act gave the U.S. Fish and Wildlife Service the authority to issue incidental take permits for situations where development of private property conflicts with the habitat needs of endangered or threatened species. In order to receive an incidental take permit, the property developer must prepare a Habitat Conservation Plan that outlines steps to avoid or minimize impacts to listed species or mitigation for unavoidable impacts. The Habitat Conservation Plan is a negotiation among diverse interests and a consensus building planning process. All affected parties must support the solution.
In June 1991, a letter from the FWS informed the County of its potential liability for third-party violations of the Endangered Species Act or a "take”. This resulted from the County issuing development permits for habitat occupied by Florida scrub-jays, thereby facilitating modification or destruction of habitat and disruption of normal scrub-jay behavior. In December 1992, the Board of County Commissioners authorized a planning process leading to the design of the Scrub Conservation and Development Plan (SCDP). The SCDP is a Habitat Conservation Plan for scrub and Florida scrub-jays in Brevard County.
The U.S. Fish and Wildlife Service funded the SCDP process. Brevard County received a $310,000 federal grant to finance all elements of the planning process. The County contracted with consultants to conduct the research necessary to draft a county-wide plan. The County also provided administrative support for the SCDP and committed a part-time environmental specialist to manage the project. The Florida Chapter of The Nature Conservancy accepted an invitation from the County to facilitate the planning process.
The Board of County Commissioners appointed two citizen ad-hoc committees to develop the SCDP- the SCDP Citizen Steering Committee and the Scientific Advisory Group. Representatives of these committees met over a period of three years in an effort to develop the goals and objectives of the SCDP.

No comments:

Post a Comment