324 U. S. NATIONAL MUSEUM BULLETIN 211 



types, that can be grouped in two broad categories — single utterances 

 and series utterances. 



The single utterances are either short or long and drawn out. 

 Among the short, incisive, single-syllable utterances are the following 

 sounds: Tschup — a "scolding" note uttered when there is a disturb- 

 ance near the nest or young, or in other situations of excitement. 

 A "flocking" note — uttered when groups take off and fly in flock 

 formation, that is shorter, higher, less loud, and with less s sound 

 and more t sound than tschup. Tup — uttered by adults when ap- 

 proaching the nest with food; more frequently used when approaching 

 the place where a young fledgling is; but also used by adults when 

 flying with older fledglings following; it is shorter, softer, lower, more 

 muffled than the tschup. A "location" note — uttered by the fledgling 

 during intervals between food-bearing visits of the parents; like tschup, 

 but weaker, it has a shorter vowel sound and a more nasal quality. 

 The "squawk" — a low, scratchy note uttered when one bird makes 

 contact with another, it is used when one bird grabs another in fight- 

 ing, when a blackbird is caught by a hawk, and also used when a 

 blackbird dives at a hawk; Mulford (1936) writes it chaw. 



Long drawn-out, single utterances, of one or more s}dlables, include 

 the following: Squeee — a very loud hoarse whistle with decided upward 

 inflection (this note and tee-uuu, described below, carry farther than 

 any of the other calls) . Schl-r-r-r-up — a comparatively subdued, tone- 

 less, whirring gurgle, aptly described by Mulford (1936) as "a rush 

 of air without vocal accompaniment"; this call and the preceeding 

 one are subject to considerable individual variations (for the associ- 

 ated activities see under "Spring" and "Courtship"). Tee-uuu — a 

 loud, clear, thin whistle with decided downward inflection, that some- 

 times becomes pit-eee or tsee-eur, but in all cases with the second 

 syllable lower in pitch than the first; it is the only clear whistled note 

 in the repertory and functions as a "warning" note (see under 

 "Enemies"). 



The second major category, series utterances, includes short notes 

 uttered in series, sometimes with a definite rythm, as follows: Kit- 

 tit-tit-tit, etc. — sometimes regular in delivery, sometimes irregular, 

 varying in quality of tone, intensity and rapidity of utterance; at 

 times it sounds more like kit-r-r kit-r-r, when it has a decided rythmic 

 effect; it is used both in the female generalized display and in bellig- 

 erent encounters, by males (rarely) when bickering over food, and is 

 frequently heard accompanying bickering at the roost (when the sex 

 of the bird cannot always be identified). The female copulatory 

 note — a soft, low, steady series of tapping notes, very different from 

 any of the other utterances — is used in the female pre-coitional display 

 (see under "Spring" and "Courtship"). Chug-chug-chug, or tucker- 



