Aegithinidae – Ioras
The ioras Aegithinidae are a small family of four passerine bird species found in Pakistan and southeast Asia. They are one of only three bird families that are entirely endemic to the Indo-malayan ecozone. They were formerly grouped with the other two of those groups, the leafbirds and fairy-bluebirds, in Irenidae.
They are small to medium small sized passerines, ranging from 11.5 to 15.5 cm in length. Overall the males are larger than the females. These are reminiscent of the bulbuls, but whereas that group tends to be drab in colouration, the ioras are more brightly coloured. The group exhibits sexual dimorphism in its plumage, with the males being brightly plumaged in yellows and greens. Unlike the leafbirds, ioras have thin legs, and their bills are proportionately longer. Calls are strident whistles; songs are musical to human ears.
Their habitats include acacia scrub, forest edge, and closed forests, as well as agricultural land and (in the common iora) gardens. They are mostly lowland birds, with most reaching only as high as the submontane forests. They are generally highly arboreal and usually occur in the tree canopy, with only very rare records of this family coming down to the ground. Ioras eat insects and spiders, which they find by nimbly gleaning the leaves of the slenderest outer twigs. The family is overwhelmingly non-migratory, although in West India there is some evidence that Marshall’s Ioras and Common Ioras are partly migratory in the seasonal semi-desert fringe.
In the two species whose male courtship displays are known, they are elaborate, culminating in the males’ parachute-style descent looking like green balls of fluff. The nests are compact open cups felted to branches with spiderweb. Females lay 2 or 3 eggs, which have pinkish speckles and red and purple lines. They incubate at night; the males, by day. Incubation lasts about 14 days. Both parents share responsibility for brooding and feeding.
There are just four species in this family, which are:
Common Iora Aegithina tiphia
Marshall’s Iora Aegithina nigrolutea
Green Iora Aegithina viridissima
Great Iora Aegithina lafresnayei
Number of bird species: 4