Enrollment Information
1-800-422-4LLU (1-800-422-4558)
Department of Earth and Biological Sciences
Faculty: William K. Hayes
Laboratory of behavioral ecology and conservation
Contact
Biology Department
Southern Adventist University
P.O. Box 370, Collegedale, TN USA
Phone: (423) 236-2924
Email: natrimm@southern.edu
Web site: http://biology.southern.edu/NevilleTrimm.htm
Birds of a feather... Yeah, Tony really enjoys hanging out with the birds. Not that I blame him. Much of the year, this bird (the Audubon's Shearwater, not Tony) typically forages far out at sea. However, during the breeding season, it will take turns with its mate incubating a single egg. Once the chick hatches out, the adults forage by day, returning only at night to tend their young. Photograph: William K. Hayes.
Tony came to Loma Linda from his family home in St. Croix, U.S. Virgin Islands. He managed to get a strong recommendation from my ornithologist brother, Floyd, who had taught Tony and supervised his undergraduate research at Caribbean Union College, Trinidad. As my first ornithology student, I encouraged Tony to study the secretive but noisy seabirds that I discovered breeding on the offshore islets of San Salvador Island, Bahamas. Poor guy...spent a couple of months mostly on his own working much of the night with the birds and trying to sleep in the stifling, mid-day heat. His hard work resulted in a nice master's thesis (read details below).
To my amazement, Tony enjoyed the birds so much that he decided (or was it my coercing?) to continue studying them for his dissertation project. You can read more about his work by going to Behavioral Ecology and Conservation of Bahamian Seabirds.
MS thesis abstract
The Audubon's Shearwater (Puffinus lherminieri), nearly pantropical in distribution, remains a poorly studied species. The subspecies P. l. lherminieri is endemic to the West Indies region. An estimated 5,000 pairs inhabit the Caribbean, but there has been a substantial decline with many colonies becoming extirpated. It is thought that as many as 3,000 pairs (60% of the West Indian population) nest in the Bahamas. In May and June of 2000, I collected data on shearwater demographics, colony site selection, burrow microhabitat, chick behavior and the effect of moonlight on the onset of calling of the Audubon's Shearwaters nesting on the satellite cays of San Salvador Island, Bahamas. The population of nesting shearwaters on the cays was estimated at 107 pairs. The size of the rock over a shearwater burrow and the percent of rock within a one-meter radius of the burrow entrance were two factors that distinguished between the burrow microhabitats of the different cays. The size of the colonies on individual cays was proportional to the availability of rocky habitat. Chick behavior varied significantly with time of day and age. Adults returned from offshore foraging areas to feed their young on 70% of the nights. Measures of chick activity were greater at night than by day and increased during the three weeks of the study. The amount of ambient light on any given night did not significantly affect the time shearwaters arrived at the colony (i.e., started calling). The detailed behavior of chick feeding bouts was described, and data on morphometrics are also reported. The information gathered in this study is integral to understanding the biology of the Audubon's Shearwater and aiding in the development of an effective conservation plan.
Trimm, Neville A. 2001. Ecology of Audubon's Shearwaters (Puffinus lherminieri) at San Salvador, Bahamas. Unpublished MS thesis, Loma Linda University, Loma Linda, California. PDF of thesis (923 K)
PhD dissertation abstract
The Audubon's Shearwater (Puffinus lherminieri), nearly pantropical in distribution, remains a poorly studied species. In the West Indies, there has been a substantial decline with many colonies becoming extirpated. From 2000-2003, I collected data on shearwater distribution, nesting habitat, morphometrics, calling behavior, and foraging behavior on Sal Salvador Island and its cays. Ninety-nine individuals were banded and 49 viable blood samples were collected. Microcassette recorders were used to record shearwater calling activity during the nightly period of peak calling activity (ca. 2100-2300 hrs.). The population of nesting shearwaters was estimated at 187 pairs. I concluded that rock plays a key role in defining prime nesting habitat. Radiotelemetry was used to determine the location of offshore foraging sites. At least one adult returned from offshore foraging areas to brood the clutch on 66% of the nights. Males attended nests at least as much as females. A lack of morphometric sexual dimorphism was confirmed. The smallest chicks grew the fastest. Storms had an adverse effect on chick growth and survival. Adults arrived at the colony later on nights with more moonlight. Parental attendance was reduced as the sun set later. The mean adult call rate (9 calls/10 min) did not change through the night. Males and females had similar call rates in all periods of the night, and chicks called more than adults in all periods of the night. Call rates were higher when two adults were at the nest, when a nest had an egg (as opposed to a chick), and when a nest had a smaller chick. Moonlight, weather, and burrow location did not affect the call rate of burrow occupants. Burrows for which chicks died had adult males that were smaller and adults that called more during early periods of the night. Dive depth tubes revealed that Audubon's Shearwaters at Green Cay dove to about 21 m. Molecular data showed an adult sex ratio of 2:1 and a chick sex ratio of 1:1. DNA sexing revealed that adults can be vocally sexed in the field accurately 91% of the time. The data gathered in this study are integral in understanding the biology of the Audubon's Shearwater and aiding in the development of effective conservation plans.
Trimm, Neville A. 2004. Behavioral ecology of Audubon's shearwaters (Puffinus lherminieri) at San Salvador, Bahamas. Unpublished PhD dissertation, Loma Linda University, Loma Linda, California. PDF of dissertation (3938 K)
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