Jason Cho’s image of the female Olive-backed Sunbird (Cinnyris jugularis) shows the bird with its tongue extended. This means that the sunbird can probe flowers whose length are longer than the bird’s bill, since the tongue extends beyond the tip of the bill.
The tongue of the male of this sunbird has been posted earlier. Generally, male sunbirds have a longer bill than that of the female. But no mention of whether the tongue of one sex is longer than that of the other. However, a longer bill means that male can harvest nectar from flowers of longer lengths. This also means that the different sexes can exploit different floral resources.
This sunbird, like all members of the Nectariniidae, harvests nectar by capillarity through its long tubular tongue. The tip ends in two helical tubes that are jagged on the inner edges. This allows for nectar to be taken into the bill by capillary action.
Image by Jason Cho.
This post is a cooperative effort between NaturePixels.org and BESG to bring the study of bird behaviour through photography to a wider audience.