Caldwell Hahn, Ph.D. (Former Employee)
Science and Products
Filter Total Items: 34
A spatial and genetic analysis of Cowbird host selection
Our study of brood parasitism patterns in forest communities revealed the egg-laying frequency and host selection patterns of female cowbirds. By integrating molecular genetics and spatial data, we have the first published estimate on cowbird laying rates in field studies. The 29 females in the study laid only 1-5 eggs each, much lower than previous estimates from captive cowbirds and extrapolat
Authors
D.C. Hahn, J.A. Sedgwick, I.S. Painter, N.J. Casna
[Book review] Cowbirds and Other Brood Parasites by Catherine Ortega. Tucson, Arizona: University of Arizona Press (1998). The Avian Brood Parasites: Deception at the Nest by Paul A. Johnsgard. New York: Oxford University Press (1997) Parasitic Birds a
We are in a golden age for the study of brood parasitism, judging from both the quantity and quality of recent scientific publications on cuckoos, cowbirds and parasitic finches by investigators working in Europe, the Americas, Africa and Asia. As Johnsgard (1997) remarks in his preface, the evolutionary, ecological, and behavioural questions posed by obligate brood parasites are among the most in
Authors
D.C. Hahn
Low abundance of microsatellite repeats in the genome of the brown-headed cowbird (Molothrus ater)
A cosmid library made from brown-headed cowbird (Molothrus ater) DNA was examined for representation of 17 distinct microsatellite motifs including all possible mono-, di-, and trinucleotide microsatellites, and the tetranucleotide repeat (GATA)n. The overall density of microsatellites within cowbird DNA was found to be one repeat per 89 kb and the frequency of the most abundant motif, (AGC)n, was
Authors
Jonathan L. Longmire, D.C. Hahn, J.L. Roach
Empirical Bayes estimation of proportions with application to cowbird parasitism rates
Bayesian models provide a structure for studying collections of parameters such are considered in the investigation of communities, ecosystems, and landscapes. This structure allows for improved estimation of individual parameters by considering them in the context of a group of related parameters. Individual estimates are differntially adjusted toward in overall mean, with the magnitude of their
Authors
William A. Link, D. Caldwell Hahn
DNA fingerprint similarity between female and juvenile brown-headed cowbirds trapped together
This DNA fingerprinting study investigates whether females of the brood parasite brown-headed cowbird, Molothrus ater, associate with their own juvenile offspring at feeding sites more often than would be expected by chance. Cowbirds lay their eggs in the nests of a variety of host species and, as far as is known, leave them to the care of foster parents. Using baited walk-in funnel traps, 36 ad
Authors
D.C. Hahn, R.C. Fleischer
Parasitism at the landscape scale: Cowbirds prefer forests
Landscape-scale examination of parasitism patterns of Brown-headed Cowbirds (Molothrus ater) revealed heterogeneous parasitism rates across the mosaic of a forest and associated old-field communities. In a two year study in Dutchess County, New York, we found a significantly higher parasitism rate in the forest-interior community (n = 301 nests; 17 species) than on the species in the adjacent and
Authors
D.C. Hahn, J. S. Hatfield
Using lice to identify cowbird hosts
Avian lice may link fledgling Brown-headed Cowbirds to the host species that raised them. Lice, if host-specific and transferred to nestling cowbirds, could serve to identify the principal host species raising cowbirds in a local area. This approach of trapping cowbird fledglings in a feeding flock, then collecting and identifying the lice they carry is economical. The alternative requires a te
Authors
D.C. Hahn, P.C. Osenton, R.W. Price
[Book review] The Eastern Screech Owl: Life History, Ecology and Behavior in the Suburbs and Countryside, by Frederick Gehlback
Review of: Eastern Screech Owl: Life History, Ecology, and Behavior in the Suburbs and Countryside. Frederick R. Gehlbach. Issue 16; Issue 2008 of W. L. Moody Jr. Natural History Series. Texas A&M University Press; 1st edition (November 1994). ISBN: 0890966095. For ornithologists and ecologists alike, Fred Gehlbach's book promises to hold both interest and information value as a comprehensive stud
Authors
D.C. Hahn
Effects of tide cycles on habitat selection and habitat partitioning by migrating shorebirds
We studied assemblages of feeding shorebirds in three intertidal habitats on the coast of New Jersey during August to document how species segregate spatially both among and within habitats and to determine the effects of tidal cycles on these patterns. The habitats were a sandy beach facing the ocean proper (outer beach), a sandy beach on the mainland side of a barrier island (inner beach), and a
Authors
J. Burger, M.A. Howe, D.C. Hahn, J. Chase
Science and Products
Filter Total Items: 34
A spatial and genetic analysis of Cowbird host selection
Our study of brood parasitism patterns in forest communities revealed the egg-laying frequency and host selection patterns of female cowbirds. By integrating molecular genetics and spatial data, we have the first published estimate on cowbird laying rates in field studies. The 29 females in the study laid only 1-5 eggs each, much lower than previous estimates from captive cowbirds and extrapolat
Authors
D.C. Hahn, J.A. Sedgwick, I.S. Painter, N.J. Casna
[Book review] Cowbirds and Other Brood Parasites by Catherine Ortega. Tucson, Arizona: University of Arizona Press (1998). The Avian Brood Parasites: Deception at the Nest by Paul A. Johnsgard. New York: Oxford University Press (1997) Parasitic Birds a
We are in a golden age for the study of brood parasitism, judging from both the quantity and quality of recent scientific publications on cuckoos, cowbirds and parasitic finches by investigators working in Europe, the Americas, Africa and Asia. As Johnsgard (1997) remarks in his preface, the evolutionary, ecological, and behavioural questions posed by obligate brood parasites are among the most in
Authors
D.C. Hahn
Low abundance of microsatellite repeats in the genome of the brown-headed cowbird (Molothrus ater)
A cosmid library made from brown-headed cowbird (Molothrus ater) DNA was examined for representation of 17 distinct microsatellite motifs including all possible mono-, di-, and trinucleotide microsatellites, and the tetranucleotide repeat (GATA)n. The overall density of microsatellites within cowbird DNA was found to be one repeat per 89 kb and the frequency of the most abundant motif, (AGC)n, was
Authors
Jonathan L. Longmire, D.C. Hahn, J.L. Roach
Empirical Bayes estimation of proportions with application to cowbird parasitism rates
Bayesian models provide a structure for studying collections of parameters such are considered in the investigation of communities, ecosystems, and landscapes. This structure allows for improved estimation of individual parameters by considering them in the context of a group of related parameters. Individual estimates are differntially adjusted toward in overall mean, with the magnitude of their
Authors
William A. Link, D. Caldwell Hahn
DNA fingerprint similarity between female and juvenile brown-headed cowbirds trapped together
This DNA fingerprinting study investigates whether females of the brood parasite brown-headed cowbird, Molothrus ater, associate with their own juvenile offspring at feeding sites more often than would be expected by chance. Cowbirds lay their eggs in the nests of a variety of host species and, as far as is known, leave them to the care of foster parents. Using baited walk-in funnel traps, 36 ad
Authors
D.C. Hahn, R.C. Fleischer
Parasitism at the landscape scale: Cowbirds prefer forests
Landscape-scale examination of parasitism patterns of Brown-headed Cowbirds (Molothrus ater) revealed heterogeneous parasitism rates across the mosaic of a forest and associated old-field communities. In a two year study in Dutchess County, New York, we found a significantly higher parasitism rate in the forest-interior community (n = 301 nests; 17 species) than on the species in the adjacent and
Authors
D.C. Hahn, J. S. Hatfield
Using lice to identify cowbird hosts
Avian lice may link fledgling Brown-headed Cowbirds to the host species that raised them. Lice, if host-specific and transferred to nestling cowbirds, could serve to identify the principal host species raising cowbirds in a local area. This approach of trapping cowbird fledglings in a feeding flock, then collecting and identifying the lice they carry is economical. The alternative requires a te
Authors
D.C. Hahn, P.C. Osenton, R.W. Price
[Book review] The Eastern Screech Owl: Life History, Ecology and Behavior in the Suburbs and Countryside, by Frederick Gehlback
Review of: Eastern Screech Owl: Life History, Ecology, and Behavior in the Suburbs and Countryside. Frederick R. Gehlbach. Issue 16; Issue 2008 of W. L. Moody Jr. Natural History Series. Texas A&M University Press; 1st edition (November 1994). ISBN: 0890966095. For ornithologists and ecologists alike, Fred Gehlbach's book promises to hold both interest and information value as a comprehensive stud
Authors
D.C. Hahn
Effects of tide cycles on habitat selection and habitat partitioning by migrating shorebirds
We studied assemblages of feeding shorebirds in three intertidal habitats on the coast of New Jersey during August to document how species segregate spatially both among and within habitats and to determine the effects of tidal cycles on these patterns. The habitats were a sandy beach facing the ocean proper (outer beach), a sandy beach on the mainland side of a barrier island (inner beach), and a
Authors
J. Burger, M.A. Howe, D.C. Hahn, J. Chase