Most birders like Willets. Why? Not so much because of any bright colors they wear. Willets, of course, are among the most drably colored of birds. What many birders like about Willets is that, among the notoriously tricky shorebirds, their flashy wing patterns and distinctive calls make them relatively easy to identify. Fortunately, for those of us who enjoy a good challenge in the field, there are actually TWO different kinds of Willets to sort out. Under current taxonomy, these two types of Willets are considered subspecies, though most evidence points to them being full species. An official “split” seems likely in the future. But whatever their taxonomic status, these two forms, the Eastern Willet (Tringa semipalmata semipalmata) and the Western Willet (Tringa semipalmata inornata) are quite distinct from one another and birders should get used to distinguishing them in the field.
Here on the Jersey Shore, most of us are very familiar with the Eastern Willet. They arrive at their salt marsh nesting grounds in early April and are noisy and conspicuous there through the spring and early summer. Their raucous pill-will-willet call is one of the signature sounds of an Atlantic or Gulf Coast salt marsh. However, their stay here is relatively brief. Most adults leave our New Jersey marshes in July and head down to their South American wintering grounds. Juveniles linger a bit longer but most are gone by mid-August with just a few lingering into September. To date, there are no winter records of Eastern Willet in New Jersey and, in fact, no certain winter records anywhere in the United States.
Though much less common, and certainly less familiar to most of us than Eastern Willet, the Western Willet actually occurs in New Jersey through a much greater portion of the year. In fact, it may be possible to see Western Willet in New Jersey during any month of the year though they are rare here in late winter and spring. Unlike their salt marsh relatives, Western Willets breed in fresh marshes and prairies of the Great Plains and interior West and winter in many coastal areas of the United States. Fall migrants begin to arrive in New Jersey in late June and July with numbers peaking in August (adults in early August, juveniles in late August). Unlike Eastern Willets, however, Westerns tend to linger in the fall and some of these birds attempt to over-winter. Small flocks are recorded with increasing frequency on Christmas Bird Counts and at least a few of these birds usually linger through the winter. The largest numbers in fall and winter are seen in the Hereford Inlet/Stone Harbor Point area in Cape May County and at the Absecon Inlet/Brigantine Island area in Atlantic County. Spring migrants are recorded only rarely but may be overlooked to some degree. And lastly, on very rare occasion a non-breeding Western Willet may over-summer in coastal New Jersey, remaining here through June—invariably in non-breeding (basic) plumage.
Distinguishing between the two Willet subspecies starts with an understanding of their status and behavior. For example, it is helpful to know that a Willet seen in New Jersey between April and mid-July is most likely an Eastern, whereas one seen between September and March is most likely a Western. But don’t just rely on the calendar. The two have slightly different habitat preferences. Although they can be seen together in a wide variety of situations, Easterns tend to prefer salt marshes and mucky tidal creeks and spend less of their time on broad sand flats or ocean beaches. While they sometimes wade belly-deep in water, they spend much more of their time on mud or in shallow water. Westerns, on the other hand, prefer those broad sand flats and ocean beaches but tend to avoid sheltered, mucky tidal creeks. And they regularly wade belly-deep in water. Both Willet subspecies roost on salt marsh pools or sod banks during high tide and it should be emphasized that their behavioral tendencies overlap broadly. A helpful hint is that Westerns have a strong association with Marbled Godwits. They breed and winter in the same areas and migrants often occur together. If any Marbled Godwits are around, check out the Willets that are with them. They will usually be Westerns. Another helpful behavioral hint: if you see a Willet prominently perched on a telephone pole, tree stump, duck blind, etc. while here in New Jersey, it will be an Eastern, every time. The only reason a Willet will risk such exposure to predators is because it is defending its nesting territory (and Westerns don’t nest here). With a little attention to behavior, it will become apparent that while Eastern Willets are here on their breeding grounds, they exhibit a wide variety of other territorial behaviors that Westerns exhibit only while on their prairie breeding grounds.
In terms of appearance, Western Willets tend to portray a more godwit-like image than Easterns. This is due mostly to their larger size, longer legs (and correspondingly longer gait), longer, thinner bills, and slightly more graceful body contour. Size can be particularly helpful in mixed flocks though there is variation with some Westerns being particularly small. In general though, Easterns are the same size or barely larger than a Greater Yellowlegs, whereas Westerns are usually distinctly larger, approaching the size of a small godwit. In coloration, all plumages of Western Willet are paler and grayer than corresponding plumages of Eastern. Though other plumage features can be useful, overall color and shade (along with structure) are probably the best field marks and, thankfully, some of the easiest to observe. Another useful feature is the molt patterns of adults. While in New Jersey, adult Eastern Willets are always in essentially full breeding plumage. Those individuals that linger into August may show a few non-breeding body feathers molting in but they still look about the same as they did earlier in the summer and they never show molting flight feathers while in New Jersey. Adult Western Willets, on the other hand, regularly show extensive body molt and often flight feather molt during late summer and fall. Indeed, many birds undergo their entire molt to non-breeding plumage while here. The reason for this difference is that both subspecies molt to non-breeding plumage at or near their wintering grounds, which, for Western Willet, includes south-coastal New Jersey. Easterns wait until they reach their South American wintering grounds before undergoing this molt.
Another characteristic worth paying attention to is voice. The primary pill-will-willet song is distinctly different between the two subspecies: Eastern’s is an urgent, rapidly repeated pidl-will-willit; Western’s is a slower, lower-pitched, more clearly annunciated p’d-weeel-will-wit with the second note more drawn-out and the last two notes more clearly separated. Unfortunately, Western Willets seldom give their primary song while here in New Jersey. That vocalization seems to be reserved mostly for birds on the breeding grounds or, to a lesser degree, on spring migration. We hear it here in New Jersey only occasionally from early fall migrants in July. Other vocalizations differ more subtly. All calls of Western average lower-pitched and more drawn-out than those of Eastern, but much overlap exists. The flight call is a loud, strident klaay-drr or klaay-dr-dr, typically with a lower, huskier, Marbled Godwit-like quality in Western and a higher, Laughing Gull-like quality in Eastern. When flushed, both subspecies utter a higher, more excited kli-li-li-li, often with a trilled quality (on average, more distinctly trilled in Western). The breeding alarm call is a sharp, repeated kleep or kalip, and is lower and more muffled in Western. The year-round alarm is a more drawn-out, screaming klaayii and variations, often with a distinctly curlew-like quality in Western.
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Photo 1 – Breeding plumage “Eastern” Willet, early June, Maine. Eastern Willets in breeding plumage have heavy dark barring overall and a brownish ground color to the upperparts. Breeding birds also have a variable but diagnostic pink tinge to the bill. Notice that the bill is relatively heavy and blunt-tipped. |
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Photo 2 – Breeding plumage “Western” Willet, mid-July, North Carolina. Breeding plumage Westerns are paler and more lightly marked than breeding Easterns, and a cold gray ground color to the upperparts is always distinctive. The structure is more godwit-like than Eastern, with a slim, fine-tipped bill, very long legs, and less compact body shape. Breeding-plumaged birds show a dark grayish base to the bill unlike the lighter and pinkish-tinged bill of breeding Eastern. |
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Photo 3 – Breeding plumage Eastern Willet, mid-June, New Jersey. Note the compact structure, brown coloration, heavily barred plumage, and pinkish-based bill. During the breeding season, Eastern Willets often perch on prominent posts, call noisily, and exhibit other territorial behaviors. Westerns exhibit similar behaviors only on their prairie breeding grounds. |
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Photo 4 – Nonbreeding plumage Western Willet, mid-August, North Carolina. Note the godwit-like structure with long legs and slim, fine-tipped bill. The overall color is cold gray. Western Willets molt to nonbreeding plumage while here in New Jersey. Easterns undergo this molt after arrival on their South American wintering grounds so never appear in nonbreeding plumage while in New Jersey. |
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Photo 5 – Juvenile Eastern Willet, late July, New Jersey. Note the relatively short, heavy, pale-based bill, short legs, and relatively dark-coloration. Juvenile Easterns show contrastier patterning on the upperparts than juvenile Westerns. Note especially the very dark, boldly spotted scapulars. |
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Photo 6 – Juvenile Eastern Willet, mid-August, North Carolina. The short legs and bill and compact body shape make Eastern Willets look less godwit-like than Westerns. The upperparts show prominent light spotting contrasting with a dark ground-color. |
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Photo 7 – Juvenile Western Willet, mid-August, North Carolina. Compared to the individual in the previous photo, note this bird’s longer legs, longer, slimmer bill, and less compact body. The patterning on the upperparts shows much less contrast than on a juvenile Eastern. Though there is much brownish color to the plumage, the feather bases show a distinctive cold gray color. |
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Photo 8 – Juvenile Western Willet, mid-August, North Carolina. A paler individual than in the previous photo. Note structure and low-contrast plumage pattern. Paler individuals such as this show a more extensively white mid-breast and forehead than do juvenile Easterns. The generally pale face contrasts with the bill, which tends to be darker than a juvenile Eastern’s. |
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