While on vacation in Colombia, a zoologist from the University of Otago spotted an extremely rare bird with both male and female characteristics. An amateur ornithologist, John Murillo, pointed out this bird, a Green Honeycreeper, to Sesquicentennial Distinguished Professor Hamish Spencer. The bird appears to have distinctive plumage, half green, as is typical of females, and half blue, as is typical of males.
“Many birdwatchers could go their whole lives and not see a bilateral gynandromorph in any species of bird. The phenomenon is extremely rare in birds; I know of no examples from New Zealand. It is very striking; I was very privileged to see it,” Prof. Spencer says in a university release.
What is gynandromorphism?
A “bilateral gynandromorph” is an organism with both male and female physical characteristics. The bird in this case had an amazing split appearance, with one side displaying female features and the other side displaying male feathers. This occurrence is extremely rare in birds.
The photographs taken of the bird, according to Prof. Spencer, are “arguably the best of a wild bilateral gynandromorphic bird of any species ever.” These photographs add significant value to the scientific community by providing a detailed look at this rare natural occurrence.
The discovery marks only the second recorded instance of gynandromorphism in this species in over a century
This is only the second instance of gynandromorphism in this species in over a century. Gynandromorphism is a condition in which an animal has both male and female characteristics in species with separate sexes.
Such cases, according to Prof. Spencer, are critical for understanding sex determination and sexual behavior in birds. Gynandromorphism is more common in species with strong sexual dimorphism, which means the males and females look very different. This phenomenon has been observed in a variety of animal species, including insects (especially butterflies), crustaceans, spiders, and even some lizards and rodents.
“This particular example of bilateral gynandromorphy—male – male on one side and female on the other – shows that, as in several other species, either side of the bird can be male or female. The phenomenon arises from an error during female cell division to produce an egg, followed by double-fertilization by two sperm,” Prof. Spencer said.
The zoologist hopes that the unusual discovery will inspire others to “treasure exceptions” because they always reveal something new.
