Jaime Collazo, PhD (Former Employee)

We compared the density and biomass of resident fish in vegetated and unvegetated flooded habitats of impounded salt marshes in the northern Indian River Lagoon (IRL) Estuary of east-central Florida. A 1-m2 throw trap was used to sample fish in randomly located, paired sample plots (n = 198 pairs) over 5 seasons in 7 impoundments. We collected a total of 15 fish taxa, and 88% of the...

We examined site characteristics and prey abundances where wintering Aythya affinis (Lesser Scaup; hereafter scaup) foraged within three regions of the Indian River Lagoon system in central Florida. We observed that scaup concentrated in the Indian and Banana rivers; however, density of prey items did not differ between foraging sites and random sites. We also found that site...

We report seasonal residency and local annual survival rates of migratory Semipalmated Sandpipers (Calidris pusilla) at the Cabo Rojo salt flats, Puerto Rico. Residency rate (daily probability of remaining on the flats) was 0.991 ± 0.001 (x̄ ± SE), yielding a mean length of stay of 110 days. This finding supports the inclusion of the Caribbean as part of the species' winter range...

Foraging habitat selection of nesting Great Egrets (Ardea alba) and Snowy Egrets (Egretta thula) was investigated within an estuary with extensive impounded salt marsh habitat. Using a geographic information system, available habitat was partitioned into concentric bands at five, ten, and 15 km radius from nesting colonies to assess the relative effects of habitat composition and...

Lesser scaup (Aythya affinis) populations have been declining since the late 1970s. One of the explanations to account for this decline, the spring-condition hypothesis (SCH), is based on the premise that scaup are limited by their ability to acquire or maintain nutrient reserves during migration to the breeding grounds, leading to an impairment of their reproductive potential. Available...

We determined the effects of fire history and a riparian-upland gradient on the breeding bird community at Fort Bragg Military Installation in North Carolina, one of the largest remnant areas of the endangered longleaf pine (Pinus palustris) ecosystem. Study sites were classified into two treatments: fire-intense (areas experiencing growing-season burns) and fire-suppressed (areas...

A variety of studies have established the value of shaded coffee plantations as habitat for birds. While the value of birds as biological controls in coffee has received some attention, the interactions between birds and other predators of insects have not been tested. We used exclosures to examine the effects of vertebrate predators on the arthropods associated with coffee, in...

We radio-tagged and released 49 captive-reared Hispaniolan Parrots (Amazona ventralis) in Parque Nacional del Este (PNE), Dominican Republic, during 1997 and 1998. Our primary objective was to develop a restoration program centered on using aviary-reared birds to further the recovery of the critically endangered Puerto Rican Parrot (A. vittata). Hurricane Georges made landfall over the...

Once abundant and widely distributed, the Bahama parrot (Amazona leucocephala bahamensis) currently inhabits only the Great Abaco and Great lnagua Islands of the Bahamas. In January 2003 and May 2002-2004, we conducted point-transect surveys (a type of distance sampling) to estimate density and population size and make recommendations for monitoring trends. Density ranged from 0.061 (SE...

Assessing stopover habitat quality and refueling performance of individual birds is crucial to the conservation and management of migratory shorebirds. Plasma lipid metabolites indicate the trajectory of mass change in individuals and may be a more accurate measure of refueling performance at a particular site than static measures such as nutrient reserves. We measured lipid metabolites...

We report first-year survival for 34 captive-reared Puerto Rican Parrots (Amazona vittata) released in the Caribbean National Forest, Puerto Rico between 2000 and 2002. The purpose of the releases were to increase population size and the potential number of breeding individuals of the sole extant wild population, and to refine release protocols for eventual reintroduction of a second...

Radio telemetry and diurnal time activity budgets were used to show that wintering Lesser Scaup (Aythya affinis) used different habitats for comfort and feeding activities at Merritt Island National Wildlife Refuge (Merritt Island), Florida and adjacent estuarine areas. Management should take this spatial consideration into account. The same data were used to determine if habitat use...