An experimental test of the contrasting-color hypothesis of red-band effects in red-winged blackbirds

Article Abstract:

The effects of red leg bands on Red-winged Blackbirds were examined to verify the hypothesis that band colors contrasting with leg color make individuals more prone to attack. Results revealed no differences between red, black and blue bands with respect to ability to provoke aggression. With red bands, however, attacks were delayed. In addition, territorial males stayed farther and displayed lower intensities. It was concluded that red bands make individuals more threatening. This goes against the contrasting-color hypothesis and instead imply that the red band effect is due to the match between band color and male epaulet color.

Bird banding, Red-winged blackbird, Color of birds, Bird coloration

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Aggression in White-crowned Sparrows: effects of distance from cover and group size

Article Abstract:

Aggression rates in White-crowned Sparrows (Zonotrichia leucophrys) depend on the closeness to cover, the number of birds in close proximity and the total number of birds foraging. The interaction rate increases with nearness to cover for a specific group size, indicating that the birds consider the areas more safe. The effect of group size decreases, however, the greater the distance from cover. The sparrows are more aggressive and more willing to fight for food in foraging locations that seem to be safer.

Birds, Sparrows

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An unusual type of sibling aggression in Black-crowned Night Herons

Article Abstract:

Research concerning the factors contributing to sibling aggression in the Black-crowned Night Heron in MN is presented. Factors considered were brood size, food availability, age disparities and sibling head swallowing.

Nestlings, Familial behavior in animals, Animal familial behavior, Herons

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