ML615173086

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RSHA?

Beobachtungsdetails

unseen whistler, suspect it's the resident RSHA BOW Vocal Array: Seven calls recognized. Kee-aah, most common call, has accent on first syllable and a drawn-out second syllable with a downward inflection (see Figure 5). This is usually performed 5–12 times, followed by a 10- to 20-min interval of silence, another 5–12 calls, then a 2- to 7-min period of silence (J. Jacobs pers. comm.). Kee-aah call is used when announcing territory in early spring, up to start of incubation, after which adults become much more quiet. This call also used as alarm. Kee-wee is a variant of this call, with accent on second syllable (Bent 1937b). Kip call, consisting of a single or repeated kip, heard when birds are particularly excited or alarmed. Keeyip call also heard when birds are excited and may grade into kip call (J. Bednarz pers. comm.). Kee-ann-errr is a drawn-out 3-syllable call given 15–25 times by displaying adults; may be shortened to kee-yerr, then changed again to a kendrick call. Kee is a soft, brief call sometimes given by female when incubating or brooding; occurs in bursts of 20–30 repetitions for as long as 30 min (M. McCrary pers. comm.). Female vocalizations are noticeably lower-pitched than those of male (M. McCrary pers. comm.). Female utters short cries before, during, and after copulation (Kilham 1981d); vocal when disturbed at nest and will call (Kee-ahh) frequently (SC). Adults will also call (Kee-ahh) if a Great Horned Owl (Bubo virginianus) or Red-tailed Hawk is found near nest site during daylight (J. Jacobs pers. comm., SC). Also call during courtship flights. In California, adults and juveniles call at any time of year, but calling becomes more regular and frequent between Nov and May, peaking Jan–Apr.

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