- Details: Written by USFWS
USFWS PRESS RELEASE
MAY 13, 2015:
Cedar Keys National Wildlife Refuge
Nesting Brown Pelicans – Cedar Keys NWR
Abandonment and Local Dynamics of the
Historical Bird Rookery at Seahorse Key
Seahorse Key, part of the Cedar Keys National Wildlife Refuge, has hosted one of the largest nesting colonies of wading birds and seabirds along the Gulf Coast of Florida for many decades. Historically the small island, located 4 miles off of Cedar Key, has harbored tens of thousands of nesting ibis, herons, egrets, brown pelicans, cormorants, and most recently, spoonbills each spring and summer. The US Fish & Wildlife Service (USFWS) has been conducting regular surveys on the colony for over 20 years. Reports from the 1950’s indicate in excess of 50,000 nests, but more recent data suggests declines to relatively stable figures of 10-20,000 nests for the past 10 years. The nesting aggregation included several listed and imperiled species, including white ibis, tricolored herons, snowy egrets, roseate spoonbills, little blue herons, and likely reddish egrets.
Recently, the colony has experienced significant changes. First, the white ibis, normally the most numerous nesting bird in the colony, did not return to the colony in significant numbers this season to nest. White ibis can be nomadic nesters, and can switch to distant locations in large numbers. Yet their numbers had been stable at Seahorse Key for decades. More notably, all the remaining nesting birds on Seahorse Key (SHK) abandoned their active nests synchronously around the third week of April and have not returned. The island is littered with thousands of abandoned eggs and nest remnants. The USFWS, in partnership with University of Florida Wildlife Ecology & Conservation Department and state Fish & Wildlife Commission experts along with the
Seahorse Key Marine lab, is investigating the cause of the abandonment, but as of yet have no conclusive results. Possibilities include disease, disturbance, a sudden and heavy increase in predation, or changes in food base. Several bird carcasses have been collected and sent off for forensic and pathological analysis. This mass abandonment is unprecedented in the long history of the SHK colony. Also of interest are the peripheral impacts of the mass abandonment on the intricate ecology of the SHK ecosystem.
Nearby Snake Key, also a part of the Refuge, has hosted a few dozen nesters in recent years. Many of this season’s displaced SHK nesters have now settled on Snake Key in an attempt to renest after their failed attempt at SHK. Survey data indicates now hundreds of nesting herons, egrets, pelicans, cormorants and spoonbills there, including most of the imperiled species. The USFWS is looking at options to protect the newly significant Snake Key rookery. The SHK lands and adjacent waters have been closed to public entry during nesting season to limit human disturbance during this critical period. A similar closure at Snake Key, in concert with state agencies and the Army Corps of Engineers, is an option. Any closure of the adjoining waters will be a public process, as the Refuge values input from local citizens, civic groups, fisherman, recreational enthusiasts, and all interested parties. In the meanwhile, the public and tour operators are urged to support protection of this unique resource and minimize disturbance to the new Snake Key colony. The USFWS has also conducted aerial surveys along the Gulf Coastal region to locate other missing nesters, but have only found small isolated colonies.
For additional information, or if individuals have any potential information on possible causes of abandonment, please contact the Cedar Keys and Lower Suwannee National Wildlife Refuges Manager at (352) 493-0238.