Sounds

Development

No information.

Vocal Array

Breeding activities begin as soon as individuals return to Arctic nesting grounds; the highly aerobatic and vocal displays are a conspicuous element of Red Knot territorial landscapes. Because many of the vocalizations are integrally associated with specific displays (Whitfield and Brade 1991), they are described together in this section.

Nettleship (1974) and Whitfield and Brade (1991) provide detailed phonetic descriptions of male songs and associated behavior from Ellesmere I. (see also A. Birula in Pleske 1928, Bird and Bird 1941, and Salomonsen 1950). At Camp Hazen, Nettleship (1974) found that individuals were present by 3 Jun, and highest song and display activity occurred between 13 and 19 Jun.

Whitfield and Brade (1991) found that first-returning males began song flights in late May on the day they arrived in breeding areas. Males rise from the ground in a steep, rapid ascent to 35–285 m, where the Song-Flight Display is performed. On reaching altitude, flight changes to an essentially broad figure eight pattern, mostly over the breeding territory, but extending past borders. The display begins with a shallow, descending glide while the Flight Song (see Fig. 4; see below) is given. The glide is followed by a shallow ascent, on stiff, quivering wing-beats and may or may not be accompanied by song. The gliding and quivering flight both last 5–10 s each, with a series of this display often lasting 5–10 min, sometimes >1 h (Whitfield and Brade 1991).

The highly variable Flight Song (Fig. 4) generally is given in 2 elements, both described as having a moaning, flutelike quality. The first, poorr-mee may be repeated many times before the second element, poorr-poorr begins. The second element typically is repeated multiple times (Fig. 4). Pitch of call elements also changes, from higher late in first elements to lower in beginning of second elements.

Song-Flight Display of one bird often stimulates neighboring birds to display, until at times 3 or 4 display simultaneously. Whitfield and Brade (1991) found that Song-Flight Displays can last 2–95 min, possibly longer.

In the weeks following arrival on breeding grounds, frequency of Song-Flight Displays decreases. At Hazen Camp, Ellesmere I., Canada, there were roughly half as many displays by early Jul, and none by the third week of Jul. Whitfield and Brade (1991) suggest that these displays, performed only by males, are terminated when mates are acquired.

Other vocalizations have been described. Parmelee and MacDonald (1960) observed that adults flushed from nests utter low peeping cries, and that parents sound a whit-whit (sometimes 3 notes) or wheat-wheat or wit-wit warning call either in flight or from the ground; chicks respond by becoming motionless. Birula (Pleske 1928) described an All-Clear Call as kjut-kjut or tuouit tuouit, similar to but softer than the alarm call, and repeated several times by parents flying 4–6 m above hidden young. Whitfield and Brade (1991) also note a rapid Chatter Yodel— yeh-yeh-yeh —used in aggressive encounters. They describe a Courtship Call as a repeated, drawn-out, high-pitched weee; the call is given in several situations, including prior to males mounting females. Whitfield and Brade (1991) describe another, mewing Glissando Call, used in nest-scrape displays, that also can precede mounting (see Behavior: sexual behavior, below); this call is lower pitched and has a greater drop in frequency than the Courtship Call. Whitfield and Brade (1991) describe a male Copulation Call (a rapid, high-pitched dee-dee-dee), given while male is mounted on female’s back. Brooding Call—irregular series of flutelike calls similar to poor note of Flight Song—is given by male, a response that evidently can be stimulated by continuous, monosyllabic cheeps from chicks (Whitfield and Brade 1991).

Red Knots generally are quiet when away from breeding grounds, although sometimes utter a subdued, somewhat nasal Whine that increases in strength and scale for about a second. This note is phonetically described as knutt by Hayman et al. (1986) and can easily be confused with a similar call note given by Stilt Sandpiper (Calidris himantopus; BAH).

Another call is commonly heard in large, flying flocks, and especially flocks departing stopover sites on migration or leaving roost sites for foraging areas. These notes are of similar quality to the knutt note described above, but are uttered in 2 repeating parts and are more drawn out; they are phonetically described as a less harsh, disyllabic knuup-knuup by Hayman et al. (1986).

None with a communicative function.