Wading Bird Rookeries - 1999

This shapefile includes estimates of percent composition of wading bird colonies located in 1999 by the Florida Fish and Wildlife Conservation Commission. The Florida Fish and Wildlife Conservation Commission conducted a statewide aerial survey during 26 January-25 June 1999 to locate waterbird (herons, egrets, ibises, spoonbills, storks, anhingas, cormorants, and pelicans) breeding colonies and estimate colony size and species composition. Fixed-wing aircraft were used to fly statewide East-West survey transects at 5-km intervals. Survey routes deviated at times to allow inventory of previously known colonies from earlier surveys. Of the 1,065 sites visited in 1999, 371 (34.8%) were active colonies supporting one or more species of waterbirds, while 694 (65.2%) were inactive sites. The largest number of active colonies (n=158, 42.6%) were located in central Florida between 27º-29ºN latitude; only 72 (19.4%) of the colonies were located in northern Florida above 29ºN; the remaining colonies (n=141, 38.0%) were found in the southern part of the state below 27ºN. Of the 371 active colonies located in 1999, 72.5% (n=269) contained 2 or more nesting species, while only 12.1% (n=45) exhibited 5 or more nesting species. The colonies in the central region tended to contain more species per colony than both the northern and southern regions of the state. Fewer colonies were found in 1999 (n=371) compared to previous statewide surveys during 1976-1978 (n=378) and 1986-1989 (n=635). Except for the brown pelican and cattle egret, most species continued a trend of nesting in smaller numbers and in fewer colonies during 1999 compared to previous surveys. Of the active colonies located in 1999, 51.2% (n=190) were previously undocumented colonies, 43.9% (n=163) were active during 1986-1989, and 21.0% (n=78) were active during 1976-1978. Only 60 (16.2%) 1999 colonies were active during the 1976-1978, 1986-1989, and 1999 surveys. This database contains records for all known and verified colonies in the state of Florida that were surveyed by the FWC during the period 1999 nesting season. Nests discovered more recently than this are not included in the database. Each year, a number of new colony sites are found. For this reason, users of this database are cautioned that the absence of a colony record for a given property does not necessarily mean wading birds are not present. This colony locator service is not meant to replace a specific on-the-ground survey. Disturbance to the colony may occur if a visit is made, and many of the colonies are located on private land. Providing these locations does not confer any permission by FWC to access private property.本形状文件（shapefile）包含由佛罗里达鱼类与野生动物保护委员会（Florida Fish and Wildlife Conservation Commission，简称FWC）于1999年调查的涉禽繁殖群百分比组成估算数据。该委员会于1999年1月26日至6月25日开展了全州范围航空调查，以定位水鸟（包括鹭鸟、白鹭、朱鹭、琵鹭、鹳、美洲蛇鹈、鸬鹚及鹈鹕）的繁殖群，并估算繁殖群规模与物种组成。调查采用固定翼飞机，以5千米间隔沿东西向全州样带飞行。调查路线有时会偏离预设航线，以便对前期调查中发现的已知繁殖群进行清查。1999年共走访1065处点位，其中371处（占比34.8%）为活跃繁殖群，栖息有至少1种水鸟，剩余694处（占比65.2%）为非活跃点位。活跃繁殖群数量最多的区域为佛罗里达中部北纬27°至29°之间，共计158处（占比42.6%）；仅72处（占比19.4%）繁殖群位于北纬29°以北的佛罗里达北部；其余141处（占比38.0%）分布于北纬27°以南的佛罗里达南部。在1999年发现的371处活跃繁殖群中，72.5%（共计269处）包含至少2种筑巢物种，仅12.1%（共计45处）的繁殖群拥有5种及以上筑巢物种。佛罗里达中部的繁殖群平均每群筑巢物种数量多于北部与南部区域。1999年发现的活跃繁殖群数量（371处）少于此前1976-1978年（378处）与1986-1989年（635处）的全州调查结果。除褐鹈鹕与牛背鹭外，多数物种在1999年的筑巢数量与繁殖群数量均呈现下降趋势，相较于此前调查结果。在1999年发现的活跃繁殖群中，51.2%（共计190处）为此前未被记录的繁殖群，43.9%（共计163处）在1986-1989年期间处于活跃状态，21.0%（共计78处）在1976-1978年期间处于活跃状态。仅有60处（占比16.2%）繁殖群在1976-1978年、1986-1989年及1999年三次调查中均处于活跃状态。本数据库收录了佛罗里达州内所有经FWC在1999年繁殖季调查确认的已知繁殖群记录。晚于本次调查发现的繁殖群未被纳入本数据库。每年均会发现大量新的繁殖群点位，因此本数据库的使用者需注意：某一地块未收录繁殖群记录，并不代表该处不存在涉禽栖息。本繁殖群定位服务并非旨在替代实地专项调查。前往繁殖群点位可能会对其造成干扰，且多数繁殖群位于私有土地之上。提供上述点位并不代表佛罗里达鱼类与野生动物保护委员会授予了进入私有土地的权限。