As a sparrow enthusiast, I was among the first ornithologists to welcome the Iago Sparrows in Europe, in the late afternoon of May 19th, 2013. Although the Plancius was docked in the harbor of Hansweert, and new land was open for colonization, the sparrows remained on deck, enjoying breadcrumbs. One male (pictured above) still resided in the vessel — on the bridge, where he had become friends with the captain.
All four sparrows were timid and passive, up until the moment I released the male from his confinement on the bridge. The other male then sought the company of the Captain’s sparrow, and the two cocks started a fight on the middle deck. I observed this behavior from close quarters.
The aggressive display ended in a clear attempt to copulate. Although I could not observe direct cloacal contact, one male definitely mounted the other and tried to copulate. Here are pictures that document this remarkable behavior.
It is striking that ‘The first case of a homosexual copulation attempt in the Iago Sparrow’ — a matter of interest to the scientific community — was observed upon first arrival of these birds in The Netherlands.
BONUS: What should happen with the Iago Sparrows in The Netherlands? [in Dutch]
BONUS:[added July 7th 2014] A write-up of this post in Dutch Birding 36: 172-173 (2014)