breeding birds and fish in enclosures with other species

[wild boar]

I have been wondering lately how breeding birds works in zoos if they are kept in enclosures with hoofstock. Species like cranes, storks, guineafowl, vultures, rheas, egrets, and pelicans are often managed in savannas replicas and with breeding reccomendations, but how are they prevented from making a nest and laying eggs anywhere.

Also, how are fish in large tanks with many species and lots of hiding places bred? I would imagine a lot of the breeding with smaller species just happens, and zoo staff don't have plans for it. As I have limited knowledge about the subject, I can think of three problems: egg predation, inbreeding, and hybridization. As for sharks, I think there are breeding recommendations but is there any way to control it?

 

[Jarne]

I have been wondering lately how breeding birds works in zoos if they are kept in enclosures with hoofstock. Species like cranes, storks, guineafowl, vultures, rheas, egrets, and pelicans are often managed in savannas replicas and with breeding reccomendations, but how are they prevented from making a nest and laying eggs anywhere.

Also, how are fish in large tanks with many species and lots of hiding places bred? I would imagine a lot of the breeding with smaller species just happens, and zoo staff don't have plans for it. As I have limited knowledge about the subject, I can think of three problems: egg predation, inbreeding, and hybridization. As for sharks, I think there are breeding recommendations but is there any way to control it?

Storks, vultures and pelicans simply don’t breed well at all in such mixed exhibits. Even when kept alone, storks don’t breed as well when pinioned. Many other species also just don’t breed in mixed exhibits: there is no nesting space, they are too stressed by hoofstock, single-sex groups, … If needed egg removal is also quite easy, either to shake them or put them in an incubator and quite often hand-rear them (after all, large hoofstock aren’t always kind to chicks).

Most fish almost never breed in on-show fish tanks. Cichlids, cardinalfish, sharks and rays are an exception to this. In the case of cichlids, other fish eat most of the fry usually. Inbreeding is not something really though about for many smaller fish species, except in some breeding programs. Sharks and rays don’t reproduce in many tanks, either because of a bad setup or because of a bad social setting. If reproduction is no longer wanted, they usually just separate the sexes. Burgers’ Zoo in Arnhem has also sterilized one of their eagle-rays, as it had more than enough pups and it was overdominating the breeding program.

Hybridisation is not as common as you would expect in large tanks, if you give them conspecifics fish usually choose their own species. Trouble mostly happens when you have one of species A, a few of species B, two of species C, etc. Blijdorp actually had some hybrid stingrays at some point, when they kept a small mixed group of motoro and leopoldi.