Blue Sky Birding – by Martin and Kathy Parker

A weekly column on bird watching in the North Bay Region which appears in the North Bay Nugget. This column was published in the August 21, 2009 edition. © Martin and Kathy Parker

Fall Shorebird Identification Can Be Confusing

August and September are the months when shorebirds are migrating through the Blue Sky Region. Unfortunately there are few locations to find these species in this area. The sewage lagoons throughout the region are the prime locations to find the various species. The best lagoons are ones which are partially drained with ample mud flats for the birds to feed upon.

The sandpipers and plovers are feeding on the various forms of aquatic life which is in the mud.

The smallest shorebirds are collectively referred to as ‘peeps’ and are all very similar in appearance. Small brownish or gray birds with long legs. They scurry around feeding. A birder requires a telescope to obtain the best views. They all prove distinct challenges in identification. The species have two or three distinctive plumages in the year and most lack obvious field marks for quick and easy identification. For beginning birders shorebird identification can be very confusing and frustrating.

There are a number of aspect which one has to take into consideration. Initially one looks at the shape of the birds. Shape can provide up to 90% of the evidence required to distinguish the species. For example the short-billed dowitcher is a as very plump bird when compared to the thin looking and very long legged lesser yellowlegs.

When looking at shape the bird’s posture may change its overall shape. A bird may be craning its neck, standing more erect and with the feathers tucked into the body. Its shape when compared to the birds of the same species adjacent to it appears to be very different. Simply watching for a while is the best way determine if the shape is due the bird being agitated or due to it being a different species.

The age of the bird needs to be considered at well. The adult birds migrate first in the fall and when they arrive will have a worn breeding plumage. During the fall migration they will be moulting into their winter plumage. The patterns on the wings and underparts will be worn and indistinct.

The young of the year migrate later and will have a fresh plumage. The pattern on the edges of the feathers on the wings and underparts will be sharply defined and neatly spaced.

The voice of different species can be used to separate similar species. For example the lesser yellowlegs has a 1 or 2 note whistle call with sounds like yew or yu-yu. The similar looking but larger greater yellowlegs has a 3-note whistle which sounds like whew-whew-whew or dear! dear! dear!. Unfortunately shorebirds usually are found in mixed flocks and it becomes difficult at times to distinguish the voices of the different species.

Birders need to be aware that leg colour is always the best method for distinguishing between species. One problem is that the leg colour can be highly variable ranging from brown to green to yellow. For example the leg colour of some least sandpipers may be a dull greenish brown resembling the black legs of a semipalmated sandpiper in poor light conditons.

Shorebirds are also wading around in the black mud of the lagoons and the legs may become discoloured from the mud and muck. The yellow legs of the least sandpiper will appear to be black due to the mud.

The smallest shorebirds which occurs regularly in the region is the least sandpiper. This sandpiper is very similar to the semipalmated sandpiper which occurs regularly in the region. Overall the least sandpiper has a brownish colouration. In contrast the semipalmated sandpiper is an overall grayish colour.

The least sandpiper has a crouching posture compared to the erect posture of the semipalmated sandpiper. Overall the semipalmated sandpiper is heavier with longer wings and legs and a thicker bill. In flight the underside of the wings of the least are much darker with a more extensive area of black along the trailing edge than the semipalmated.

The leg colour of a prime condition least sandpiper is yellow and the semipalmated is black. As noted earlier this is not always reliable due to caked mud and muck on the legs.

On August 12 Fred Pinto and Kevan Cowcill visted some of the islands in the West Arm of Lake Nipissing in search of migrating shorebirds. The next day they visted the Warren and Verner lagoons. On both of these trips they spotted both least and semipalmated sandpipers. Both are present in the region so one can take the time to identify the two species.

Martin Parker and Steve O’Donnell have been visiting the Powassan lagoon regularly and have not detected any semipalmated sandpipers at that lagoon this fall.

Pinto and Cowcill also had American golden plovers at the Verner lagoon on August 14. This plover is very similar to the black-bellied plover, another regular fall migrant in the region. The American golden plover typically prefers areas with short grass such as sod farms and golf courses. The American golden plover is the smaller of the two species with a smaller head and bill. When flying the black colour in the ‘armpits’ at the base of the underside of the wings is the distinctive feature of the black-bellied plover.

Brent Turcotte on September 19 observed a small flock of six sanderling on the beach of Lake Nipissing near the mouth of Chippewa Creek in North Bay. The sanderling typically prefers sandy beaches and can be watched darting back and forth with the waves. Sanderlings should be present on the beach at for the next few months.

The next activity of the Birdwing Group of North Bay will be an evening outing to the Cranberry Trails at Callander under the leadership of Martin Parker. The group will be meeting at the North Bay Information Centre on Tuesday, August 25 at 6:30 p.m. and then proceeding to the trail. They will be looking for fall migrants. Everyone is welcome to participate.

We welcome your observations of the fall migrants for future columns. Please submit your observations to mkparker@ontera.net