Killdeer are one of the most recognizable and widespread shorebirds in Oregon, found in a variety of open habitats, often far from water, like fields, lawns, golf courses, and even gravel rooftops. They are well-known for their distinctive "kill-deer" call and their dramatic "broken-wing" display to lure predators away from their nests.

When it comes to telling males and females apart, Killdeer exhibit almost no sexual dimorphism in their plumage. This means that, visually, adult males and females look virtually identical in the field.

General Appearance of Adult Killdeer (both sexes):
Size and Shape: They are medium-sized plovers, about the size of an American Robin, but with longer legs and a more slender build. They have a relatively large, rounded head and a short, stout bill.
Coloration:
Upperparts: Brownish-tan on the back, wings, and crown.
Underparts: Crisp white on the belly.
Breast Bands: Their most distinctive feature is two bold black bands across their white chest. This sets them apart from other plovers in North America, which typically have only one.
Face: A brown face with white forehead, a black stripe above the white forehead, and black patches around the eye. They also have a white collar with a black upper border.
Rump and Uppertail Coverts: A bright, rusty orange-buff (sometimes described as rufous) rump is very conspicuous in flight.
Tail: Long and pointed, with a black band near the tip and white outer tail feathers.
Bill: Short, black, and pointed.
Legs and Feet: Flesh-colored or pale yellowish-tan.
Eyes: Dark brown with a prominent red eye-ring.

Plumage: As mentioned, the feather coloration and patterns are essentially the same for both sexes. There are no consistent differences in the boldness of the black bands or the intensity of the rufous rump.
Size: While some studies suggest females might be *slightly* larger or heavier on average, this difference is generally too minimal to be a reliable field mark. Individual variation within sexes often overlaps.

Since visual identification is so challenging, behavioral observations, especially during the breeding season, are more likely to offer clues:

1. Courtship and Nest Scrape Ceremony:
During the breeding season, males often initiate "scrape ceremonies." The male will lower his breast to the ground and scrape a shallow depression with his feet, attempting to attract a female to this potential nest site.
Males may also perform elaborate courtship flights, flying high with slow, deep wingbeats and giving their "kill-deer" call repeatedly.

2. Incubation Duties:
Both male and female Killdeer share incubation duties for their clutch of typically 4 eggs.
Males tend to incubate more often at night**, while females typically sit on the eggs during the day. If you observe a pair at a nest over an extended period, this shift in incubation could help determine sex.
Both sexes develop brood patches (bare patches of skin on the belly for incubating eggs).

3. Vocalizations: Both sexes give the characteristic "kill-deer" call, which is their namesake. There isn't a readily apparent difference in their calls that reliably indicates sex.

4. Nest Protection (Broken-Wing Display): Both males and females are famous for the "broken-wing" display, where they feign injury to distract predators (including humans) away from their nest or young. Both parents participate equally in this defense.