Sunning behaviour in ibis (Threskiornithidae) - Observations on four species and conclusions for captivity care

In this article, we describe and compare the sunning behaviour of four ibis species, which represent four different genera (Threskiornis, Plegadis, Geronticus and, for the first time, Eudocimus). Sunning is a genetically fixed form of comfort behaviour. Sunning behaviour can be divided in an initiation and ascending. When sunning, each species has its specific body and wing posture. For each species, we show the typical sunning behaviour and variations of it, also the factors which initiate and influence it.While the other ibis species have similar postures, the genus Eudocimus seems to represent a separated taxon. Sunning behaviour only occured with full sunshine (>11000 Lux) and when temperatures reached a species-specific minimum. Never sunning and drying were combined in any ibis species.Sunning behaviour does not seem to be vital, but it has a strong “wellness” aspect. It can be seen as a hint for good care, as sunning behaviour is shown under optimal conditions. In addition, it is a very attractive behaviour for visitors.