Biology ETDs

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Three avian communities (spruce-fir, aspen, and pinon-juniper) were studied from April to August, 1973, in the Sangre de Cristo Mountains, in north-central New Mexico. An additional pinon-juniper community was studied from June to August, 1973, in the Manzano Mountains, east of Albuquerque, New Mexico. The Emlen technique (1971) was used and evaluated. Transects one mile in length were set-up in the above communities and song and non-song detections were tabulated out to a 412-foot (126 meter) line on both sides of the transect. This census method appears more realistic, in terms of community complexity, than the expansion census methods; however, at the present time, direct comparisons are lacking. My values for number of birds per 100 hectares were an order of magnitude lower than those obtained by Tatschel (1967) and Young (1973). Consuming and standing crop biomass figures were tabulated and compared for each community. The spruce-fir and aspen communities showed the greatest similarity. Respiration energy figures were computed using the Lasiewski-Dawson (1967) equation and a conversion factor (for molt, breeding, thermoregulation, etc.) of X 2.5 from Holmes and Sturges (1973). These data showed two energy peaks; one in May, representing spring migration into and through the communities, and the other in late July, representing the movement of immatures. Diversity indexes (H'1 H'max and H'/ H' max) were figured and indicated that the pinon-juniper communities had the greatest avian diversity. The aspen community showed the lowest diversity index and appears to be a reflection upon both the homogeneity and lack of vegetational layering of the stand.



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Degree Name


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Department Name

UNM Biology Department

First Committee Member (Chair)

J. David Ligon

Second Committee Member

James Roman Gosz

Third Committee Member

Clifford Smeed Crawford

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Biology Commons