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Parental Care And Clutch Sizes In North And South American Birds, Thomas E. Martin, P. R. Martin, C. R. Olson, B. J. Heidinger, J. J. Fontaine
Parental Care And Clutch Sizes In North And South American Birds, Thomas E. Martin, P. R. Martin, C. R. Olson, B. J. Heidinger, J. J. Fontaine
Nebraska Cooperative Fish and Wildlife Research Unit: Staff Publications
The evolutionary causes of small clutch sizes in tropical and Southern Hemisphere regions are poorly understood. Alexander Skutch proposed 50 years ago that higher nest predation in the south constrains the rate at which parent birds can deliver food to young and thereby constrains clutch size by limiting the number of young that parents can feed. This hypothesis for explaining differences in clutch size and parental behaviors between latitudes has remained untested. Here, a detailed study of bird species in Arizona and Argentina shows that Skutch's hypothesis explains clutch size variation within North and South America. However, neither Skutch's hypothesis …
Shrinkage Of Inland Silverside Larvae Preserved In Ethanol And Formalin, Mandy K. Cunningham, William F. Granberry, Kevin L. Pope
Shrinkage Of Inland Silverside Larvae Preserved In Ethanol And Formalin, Mandy K. Cunningham, William F. Granberry, Kevin L. Pope
Nebraska Cooperative Fish and Wildlife Research Unit: Staff Publications
Length measurements of preserved larval fish are necessary in many types of larval fish surveys. If the fixative causes significant shrinkage, then the preserved lengths cannot be used to indicate accurate live lengths. The objective of this study was to determine how preservation in two different concentrations of formalin and ethanol affects the total length of larval inland silversides Menidia beryllina. Larvae were measured (nearest 0.1 mm) and individually fixed in one of four fixative treatments (80% ethanol, 100% ethanol, 5% buffered formalin, and 10% buffered formalin). Fish were remeasured (nearest 0.1 mm) at 15 min; 4 h; and …