The use of visual barriers to reduce aggression among a group of marabou storks (Leptoptilos crumeniferus)

Marabou storks are one of the most commonly held birds in zoos, but the captive population faces challenges related to high mortality. One of the most common causes of death among captive marabou storks is conspecific aggression. There is a pressing need to better understand how to manage this aggression. One method that has been used successfully to reduce aggression in other species is the addition of visual barriers to the enclosure, though there are no published studies on their effect on storks. We studied the behavioral changes in a group of 2.2 marabou storks following the addition of two shade cloth barriers to their enclosure; we documented all occurrences of aggressive behavior, as well as time spent proximate to the barriers (or the space between barrier posts, when the shade cloth was removed) and time spent using the barriers to block the view of other storks. The presence of the shade cloth did not change the amount of time storks spent proximate to the barriers, nor did they spend more than 2% of their time using the barriers to block other storks, but the presence of the barriers significantly reduced displacement activity. Barriers may afford captive marabou storks an important means of escaping conflict, as flight-restriction and housing in an enclosure can limit their opportunities to give a signal of retreat or submission.