Evolution of the house finch on Santa Cruz Island, California

1971 ◽  
Vol 49 (5) ◽  
pp. 675-684 ◽  
Author(s):  
Dennis M. Power
Keyword(s):  
Gene Flow ◽  
Island Population ◽  
House Finch ◽  
Santa Cruz Island ◽  
Santa Cruz ◽  
House Finches ◽  
Niche Variation ◽  
Male House ◽  
Variation Model

Male house finches of Santa Cruz Island, California, have, on the average, slightly larger bills and longer legs than do birds of the same species from the adjacent mainland. There is also somewhat less variability in the island population. These trends are discussed in reference to prevailing theory on evolution in island and colonizing populations, including Grant's hypothesis, the niche-variation model, the founder principle, and rates of gene flow.

Nest mites (Pellonyssus reedi) and the reproductive biology of the house finch (Carpodacus mexicanus)

2000 ◽  
Vol 78 (12) ◽  
pp. 2126-2133 ◽  
Author(s):  
Andrew M Stoehr ◽  
Paul M Nolan ◽  
Geoffrey E Hill ◽  
Kevin J McGraw
Keyword(s):  
Reproductive Biology ◽  
Carpodacus Mexicanus ◽  
House Finch ◽  
East Central ◽  
House Finches ◽  
Male Plumage ◽  
Initial Appearance ◽  
Almost All ◽  
Mite Infestations ◽  
Male House

We investigated the effects of a hematophagous nestling mite (Pellonyssus reedi, Acari: Macronyssidae) on the reproductive biology of the house finch (Carpodacus mexicanus) in east-central Alabama, U.S.A. Mites were absent from nests for the first half of the breeding season, but after their initial appearance they increased in number and were present in almost all nests. High nest-mite levels were associated with decreased nestling mass and hematocrit, but not with decreased nestling tarsus length. Experimental elimination of mites from some nests confirmed that the effects observed were mite-induced, not seasonal. The plumage colour of breeding adult male house finches was not correlated with nest-mite levels, nor did it appear that redder males' offspring suffered less from the effects of mites. Adult house finches fed nestlings from highly parasitized nests less often than those from nests with few or no mites. It appears unlikely that mites are directly involved in the sexual selection of bright male plumage coloration in this population of house finches. However, it is known that early-nesting females preferentially pair with redder males, therefore the benefit of nesting early and avoiding mite infestations is greater for redder male house finches.

scholarly journals Body size, sex and high philopatry influence the use of agricultural land by Galapagos giant tortoises

Oryx ◽  
2021 ◽  
pp. 1-10
Author(s):  
Kyana N. Pike ◽  
Stephen Blake ◽  
Freddy Cabrera ◽  
Iain J. Gordon ◽  
Lin Schwarzkopf
Keyword(s):  
National Park ◽  
Agricultural Land ◽  
Large Male ◽  
Gps Data ◽  
Santa Cruz Island ◽  
Santa Cruz ◽  
Agricultural Areas ◽  
On Farm ◽  
Human Wildlife Conflict ◽  
Privately Owned

Abstract As agricultural areas expand, interactions between wild animals and farmland are increasing. Understanding the nature of such interactions is vital to inform the management of human–wildlife coexistence. We investigated patterns of space use of two Critically Endangered Galapagos tortoise species, Chelonoidis porteri and Chelonoidis donfaustoi, on privately owned and agricultural land (hereafter farms) on Santa Cruz Island, where a human–wildlife conflict is emerging. We used GPS data from 45 tortoises tracked for up to 9 years, and data on farm characteristics, to identify factors that influence tortoise movement and habitat use in the agricultural zone. Sixty-nine per cent of tagged tortoises used the agricultural zone, where they remained for a mean of 150 days before returning to the national park. Large male tortoises were more likely to use farms for longer periods than female and smaller individuals. Tortoises were philopatric (mean overlap of farmland visits = 88.7 ± SE 2.9%), on average visiting four farms and occupying a mean seasonal range of 2.9 ± SE 0.3 ha. We discuss the characteristics of farm use by tortoises, and its implications for tortoise conservation and coexistence with people.

scholarly journals Isotopic Niche Segregation among Darwin’s Finches on Santa Cruz Island, Galápagos

Diversity ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 147
Author(s):  
Mariana Villegas ◽  
Catherine Soos ◽  
Gustavo Jiménez-Uzcátegui ◽  
Shukri Matan ◽  
Keith A. Hobson
Keyword(s):  
Three Dimensional ◽  
Sympatric Species ◽  
Isotopic Niche ◽  
Museum Specimens ◽  
Santa Cruz Island ◽  
Santa Cruz ◽  
Δ13c And Δ15n ◽  
Darwin's Finches ◽  
Darwin’S Finches ◽  
Foraging Guilds

Darwin’s finches are a classic example of adaptive radiation involving differential use of dietary resources among sympatric species. Here, we apply stable isotope (δ13C, δ15N, and δ2H) analyses of feathers to examine ecological segregation among eight Darwin’s finch species in Santa Cruz Island, Galápagos collected from live birds and museum specimens (1962–2019). We found that δ13C values were higher for the granivorous and herbivorous foraging guilds, and lower for the insectivorous finches. Values of δ15N were similar among foraging guilds but values of δ2H were higher for insectivores, followed by granivores, and lowest for herbivores. The herbivorous guild generally occupied the largest isotopic standard ellipse areas for all isotopic combinations and the insectivorous guild the smallest. Values of δ2H provided better trophic discrimination than those of δ15N possibly due to confounding influences of agricultural inputs of nitrogen. Segregation among guilds was enhanced by portraying guilds in three-dimensional isotope (δ13C, δ15N, and δ2H) space. Values of δ13C and δ15N were higher for feathers of museum specimens than for live birds. We provide evidence that Darwin’s finches on Santa Cruz Island tend to be generalists with overlapping isotopic niches and suggest that dietary overlap may also be more considerable than previously thought.

scholarly journals SEROLOGIC SURVEY OF THE ISLAND SPOTTED SKUNK ON SANTA CRUZ ISLAND

2006 ◽  
Vol 66 (4) ◽  
pp. 456-461 ◽  
Author(s):  
Victoria J. Bakker ◽  
Dirk H. Van Vuren ◽  
Kevin R. Crooks ◽  
Cheryl A. Scott ◽  
Jeffery T. Wilcox ◽  
...  
Keyword(s):  
Santa Cruz Island ◽  
Santa Cruz ◽  
Serologic Survey

Identifying Shell Middens With Historic Aerial Photos: An Example From California's Santa Cruz Island

2017 ◽  
Vol 14 (1) ◽  
pp. 113-122 ◽  
Author(s):  
Jon M. Erlandson ◽  
Kristina M. Gill ◽  
Amy E. Gusick ◽  
Adriane E. Dorrler
Keyword(s):  
Santa Cruz Island ◽  
Santa Cruz ◽  
Shell Middens ◽  
Aerial Photos
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