A Marabou in Kenya swallowed an entire bloody butcher knife that had been set down momentarily by an abattoir worker. The spotlessly clean knife was found a few days later where the stork had apparently regurgitated it in the same manner it would indigestible natural foods. Most colonies consist of 20-60 pairs but may number in the thousands. Individuals will return to the same colony and nest site year after year. Prime colony locations are relatively free of disturbance, near marshy habitat, and reasonably close to good food sources.
Male storks arrive at the nesting site first and establish themselves on a territory.
They fully inflate their gular sacs and greet all arrivals with equal hostility. A courting female will respond to this aggression with passivity and a submissive display until she is accepted as a mate. Thereafter she will inflate her own gular sac and repel subsequent intruders. Nests are placed in trees or occasionally on cliff-ledges. Though nest locations can be reused every year, the nest itself usually requires extensive renovations.