Cameron Cox has traveled throughout the USA pursuing birds over the past eight years. Much of the ground work for this article was laid in the spring and summer of 2004 when he worked on a shorebird project in the Delaware Bay. An optics junky virtually since he first touched binoculars, it is no surprise that he now works as a birding specialist for Nikon Sport Optics. (Though those who know him may be surprised that he managed to obtain any kind of steady employment) When not attending birding festivals throughout the country for Nikon, he resides in Seattle Washington.
The peeps, common slang for the five smallest North American sandpipers, tend to create more identification headaches than the rest of the shorebirds put together. Most identification literature does little to help, keying in on bill length and shape and a host of relatively subtle plumage marks that vary with age. For the three smallest peeps, differences in structure, not related to the bill, are usually downplayed with the implication that they are too subtle to be useful.
But is this really true? Most experts stress the importance of structure in shorebird identification, so it seems logical that structure should play a key role in the identification of the most difficult group of shorebirds. In this article, I explore various non-plumage related characteristics that may be of use in the identification of peeps. I hope to show how much can be done without relying on plumage.
The method of identification presented in this article is only effective if the observer is willing to take birding beyond the simple field mark-based approach most birders are taught as beginners and look at birds critically. This takes an initial investment of time to study birds, but it pays dividends by allowing one to more confidently and consistently identify birds, and do so at greater distances. Be aware that at any point an individual bird can adopt an unusual posture or behavior. Therefore, while first impressions can be useful, it is important to watch individuals over an extended period. By doing so you will not only understand the typical appearance of a species, but will also know how various behaviors or situations can create changes in the typical appearance. Use caution when applying the methods described in this article to photographs, which often freeze a bird in an odd posture leading to false impressions.
In this article peeps are divided into three different categories: least, standard, and long-winged peeps. It is usually simple to place an individual peep into the appropriate category. Categorizing an unknown peep should be your first step, because by doing so, you will have identified it or be left with only two possibilities. Therefore, each section begins with an overview of the group and how its members are separated from the other two groups. More detailed, species-specific information follows the overview.
We begin with the most distinctive group, containing only one species, the Least Sandpiper. It is the smallest shorebird in the world, clearly smaller than the other peeps in direct comparison. (Fig. 6) It rarely forms large, tightly packed flocks. Instead, Least Sandpipers usually spread themselves out along muddy edges, near vegetation that can be used as cover. They typically feed from a crouched position, often almost brushing the ground with their chest. (Fig 4) Their “knees” (tibia-tarsus joint) are often bent sharply as they delicately pick food from the surface. Their feet can be planted so far forward that they look like they are feeding between their toes. (Fig 1) It is safe to identify any peep that does this, for an extended period, as a Least. They often seem quite nervous, frequently glancing around and freezing in place at any sudden noise. (Fig. 2)
Least Sandpipers look dinky, with small, rounded heads and short bills that taper to a fine point. (Fig 4) Their large, round eye dominates the face and gives them a wide-eyed appearance. This is due in part to the lack of a strong supra-orbital ridge, a ridge of bone that runs above the eye, slightly more prominent in other peeps giving them a squinting appearance. Their primaries are short, with no extension past the tertials. (Fig. 5) The leg bones and joints are noticeably finer than those of other peeps.
In flight, Least Sandpipers resemble small bats. They have short, rounded wings that are noticeably kinked back at the wrist joint. In the fall, adults often show noticeable gaps in the flight feather caused by molt. In a mixed flock of peeps overhead, their wings clearly have narrower bases than those of other peeps. They frequently seem excluded from the main body of a mixed flock, relegated to the edges or the back of the flock. As they buzz by, they almost always give their shrill, ringing “trreee” call.