Code

CCBTR-02-06

Publication Date

2002

Abstract

FalconTrak is a multi-organizational partnership designed to investigate survivorship and movement patterns of young peregrine falcons in the mid-Atlantic region. The goal of this project is to collect information that may be used to improve the management of this species in the region. During the 2001 breeding season, 19 young falcons were fitted with solar-powered, satellite transmitters and tracked until they died or transmitters failed. These birds included captive-reared birds that were released in the mountains, wild-reared birds that were translocated for release in the mountains, and wild-reared birds that were fledged in situ within coastal territories. Nearly 50% (9 of 19) of the falcons were lost in the first 6 months of tracking. All of these birds were lost in the initial 10 weeks after fledging as they were gaining experience flying and hunting. The largest source of mortality was collisions with artificial structures such as utility lines and buildings. Remaining birds were lost to storms or unknown causes. All birds that survived into the late fall months exhibited the same basic seasonal pattern in movement rates. Birds appear to develop through a pre-dispersal period, a dispersal period, and eventually enter a post-dispersal period that was likely the functional equivalent of a winter range. The pre-dispersal period averaged 50 days in length and was characterized by short movements that were focused on the natal or hack site. This period corresponds to the period of dependency when falcons require food supplements as they learn to hunt on their own. The dispersal period begins with a definitive dispersal flight away from the natal site and is characterized by broad-scale movements that may be punctuated by shorter movements that are focused on temporary staging areas. This period lasted approximately 100 days. All of the birds that were hacked in the mountains ultimately gravitated to the coast and occupied staging sites for varying periods of time. All of the birds that fledged within coastal sites, remained on the coast through the tracking period. Once on the coast, birds moved both north and south and many birds spent significant periods of time in major metropolitan areas such as Baltimore, Philadelphia, Trenton, New York City, and Boston. Other staging areas included more natural coastal habitats such as barrier islands and extensive complexes of open marshes. The general preference for the coast appears to be a response to prey availability which is highest in coastal areas during the late fall and winter and underscores the importance of coastal habitats in the life cycle of mid Atlantic peregrines. Only 3 of the 9 birds that were tracked into the late fall months exhibited definitive southerly migration movements. These 3 birds represented all of the geographic situations included in the project. Two of these birds migrated along a coastal route and made a transoceanic flight from the Outer Banks of North Carolina. One bird made landfall just north of Grand Bahama Island and over the next 2 weeks made its way through Cuba and to the eastern side of the Dominican Republic. The second bird made landfall in northern Florida and over the next month made its way to Miami. The third bird flew along the fall line of the coastal plain south to South Carolina.

Species

Peregrine Falcon

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