Assessing saddle-billed stork (Ephippiorhynchus senegalensis) pair-bonds and breeding behavior using behavior observed during multiple breeding seasons.

Despite the fact that saddle-billed storks (SBS) are housed in zoos around the world, few successful hatches have been recorded. At Disney's Animal Kingdom® we conducted observations on two pairs of SBS during multiple reproductive periods to assess the relative strength of their pair-bonds and their reproductive success. We accomplished this through observations of rates of social behaviors, such as wing displays and aggression, rates of nest construction, time on and near the nest, and egg production. We determined that one pair was more successful than the other because it produced and incubated eggs during all breeding seasons. We found that the male from this more successful pairing displayed higher rates of nest presence, nest construction, and time on the nest than all other individuals. The more successful pairing also spent more time in close proximity than the less successful pair. During incubation, the male and female from the more successful pair spent similar amounts of time at the nest and incubating the eggs, but this pair never successfully hatched an egg during our study period. Ultimately, our results suggest that the pair-bond between the more successful pair was stronger than that of the other pair because they spent more time in close proximity and performed higher rates of nesting behaviors. This study highlights the lack of understanding of the factors that lead to successful SBS pairings in zoos, and emphasizes the need for future studies of their nesting behavior and pair compatibility to increase reproductive success.

Chemical and surgical interventions to alleviate intraspecific aggression in male collared lemurs (Eulemur collaris).

To reduce male-male aggression in collared lemurs (Eulemur collaris) at Disney's Animal Kingdom, a clinical trial of leuprolide acetate (Depo-Lupron) injections through one breeding season (24 wk), followed by surgical castration after the breeding season was implemented. Daily behavioral observations to record occurrences of aggression were conducted before and during the injection period, as well as after castration. Fecal sample collection began 2 wk before the first injection and continued throughout the clinical trial to determine testosterone metabolite concentration. Samples were collected 3 times per week. Fecal collection and behavioral observation continued for 5 mo after castration. Fecal samples from 3 intact males from other institutions were obtained to compare testosterone values. While the lemurs were treated with Depo-Lupron, testosterone concentrations spiked immediately after injection, and then returned to pretreatment, nonbreeding-season levels after varying lengths of time. Analysis of the behavioral data indicated that aggression was not significantly reduced with Depo-Lupron treatment. However, after castration, contact aggression and wounding decreased to zero. Although the sample is small, this study presents the first documented data on the effects that chemical treatment with Depo-Lupron and surgical castration have upon hormone levels and aggressive behavior in eulemurs.