Wilson's Phalarope

Wilson's Phalarope - A Late Summer Migrant

Wilson's Phalarope

 Riverview Marsh was rewarded recently (in late summer) by the arrival of several interesting species of shorebirds.  Among them was a Wilson's Phalarope which remained for about a week, feeding heavily to build up energy for its long flight south.  Three of us were there looking at and photographing the Marbled Godwits when very near us swam a phalarope.  It took a close examination of the many photographs I was able to get in order to identify this shorebird.  See this blog for a post on the Marbled Godwits.

Phalaropes are special shorebirds which are often pelagic, are often seen swimming and are sleek and very agile.  They can be confused with other species of shorebirds but after taking a few moments to watch their behaviour, one can identify them as phalaropes.  We have three species of phalaropes; Wilson's, Red-necked, and Red.  See another post on this blog for a description of the Red-necked Phalarope.

Phalaropes are special in that they have partially lobed feet (Wilson's has the least lobed feet) and a very dense plumage.  Presumably these facts make it easy for them to swim.  They feed on the water and often spin in circles to stir up food, the larvae, crustaceans and insects that constitute their diet.  They will also feed on land where they still also walk in circles.  Another interesting fact about this group of species is that they exhibit gender role reversals.  The females are larger and more brightly coloured than the males.  The females court the males in spring and after she lays the eggs, she assumes her duty is finished!  The males incubate the eggs and raise the chicks.  They have two plumages per year, breeding and non-breeding (winter) plumages.  Those that pass through here are often in transition and that can make identification difficult.

Wilson's Phalarope

The Wilson's Phalarope (Phalaropus tricolor) is usually generally lighter in colour than the other two species.  It is the largest of the 3 species ( 24 cm/9.3 in long).  It has a long, thin, black needle-like bill which helps separate it from other shorebird species.  In breeding plumage the female has a large rufous stripe on the face and neck, a light orange breast, white throat, gray and rufous on the back, and a very light gray crown with a white supercilium (line above the eye).  The male in breeding plumage is similar but much duller in colour.  In non-breeding plumage the black legs turn yellowish olive, the upper plumage is light gray, the crown remains light gray and there is a light gray post ocular stripe.  So, you can see that the individuals in transition can be difficult to identify.  We occasionally see individuals in breeding plumage here in the spring and, as in this case, individuals in non-breeding plumage in the fall (or in transition).

Wilson's Phalarope

As you can see in the photo above, this transitional individual is losing the rufous stripe on its face and neck; the orange on the breast is gone, the black eyeline is fading, and the gray on the crown and back of the neck are becoming lighter in colour.  Also note that the legs are yellow which helps distinguish the Wilson's from our other two phalarope species.

Wilson's Phalaropes breed in interior wetlands throughout western North America.  Some breed along the shores of James Bay in northern Ontario.  They winter in South America especially in inland saline lakes in Argentina, Bolivia, Chile and Peru.  Their preferred breeding habitats include grassy borders of shallow lakes, marshes and reservoirs.  They nest on the ground in a scrape lined with grasses.  The usual four buff eggs are incubated about 18-21 days.

Wilson's Phalarope

The Red-necked and Red Phalaropes spend considerable time at sea.  We often see large flocks of phalaropes in Passamaquoddy Bay and the Gulf of Maine in late summer.  The Wilson's is less adapted to pelagic habitats so rarely is seen at sea.  They spend their time on ponds inland and this makes the species vulnerable to habitat degradation and loss.  They have been especially vulnerable on prairie habitats where draining of wetlands and water diversion projects have robbed them of major staging areas during migration.

The Wilson's Phalarope is named after the renowned ornithologist, Alexander Wilson.  It was first described as a species in 1819 by Louis Jean Pierre Vieillot, a French ornithologist.  The term, phalarope, comes from the Greek, phalaris, which means 'coot' and pous, which means 'foot'.  Given that the coot has lobed toes, it follows that the phalarope has an appropriate name.  It is 'neat' how language has evolved.