A Dutch mystery: Can you guess which duck species have hybridized?

A hybrid duck on Schiermonnikoog requires expert identification skills.

Hybrid ducks are common. But when you encounter one in the wild, it can be tricky to figure out which species have intermingled. A recent paper in Dutch Birding describes the quest of several Dutch birders to identify a hybrid duck on the island of Schiermonnikoog. Let’s see if you can guess the right answer. Here is the duck:

A mystery duck on Schiermonnikoog (picture by Thijs Glastra)

 

An Escapee?

This picture (among others) was shared on social media and led to the suggestions that it might be an Australasian Shoveler (Anas rhynchotis). This species is known to escape from captivity in the Netherlands. Have a look at a picture of an Australasian Shoveler. Could the mystery bird belong to this species?

An Australasian Shoveler (from http://avithera.blogspot.se/)

 

Or a Hybrid?

There are some similarities, but it is obvious that our mystery bird is not an Australasian Shoveler. Two other birders decided to have a closer look at the bird on Schiermonnikoog. They managed to lure it to the shore by playing the sound of a Northern Shoveler (A. clypeata). Based on the combination of characters, they quickly concluded that it concerns a hybrid. An obvious candidate was Northern Shoveler x Blue-Winged Teal (A. discors).

The species that might have produced the mystery bird: Norther Shoveler (left) and Blue-winged Teal. (from http://www.allaboutbirds.com/)

 

But which hybrid?

Mystery solved? Not quite. This hybrid is just one of many other possible combinations. A Northern Shoveler might have crossed with a Cinnamon Teal (A. cyanoptera) or Red Shoveler (A. platalea). It could even be a backcross… Clearly, a difficult decision. But the authors are quite convinced about this conclusion:

There are several constant differences between hybrids Northern Shoveler x Blue-winged Teal and Northern Shoveler x Cinnamon Teal that we believe permits robust identification. The former shows a white to pale cream-coloured breast, strong spotted/marbled pattern on breast, dark markings on flank and clean white patch on rear flank, and the iris colour is typically darker. Hybrids involving two shoveler species (Red x Northern Shoveler, Australasian x Northern Shoveler) are also different from Northern Shoveler x Blue-winged Teal, in particular as they are heavy-headed birds with bill and body size similar to Northern.

Do you agree? Feel free to comment below.

A hybrid between Northern Shoveler and Cinnamon Teal (picture by Rob Fowler)

 

References

van Bemmelen, R.S.A., Lehmhus, J. & Mlodinow, S.G. (2018) Hybrid Northern Shoveler x Blue-winged Teal on Schiermonnikoog, Netherlands, in May 2014, and identification and WP occurrence. Dutch Birding, 40:71-81.

 

The paper has been added to the Anseriformes page.