GAMBEL'S WREN-TIT 91 



territorial dispute, the bird giving the song may be assumed to be 

 the male. The song appears to have a double purpose. It is used 

 as an announcement of territorial possession. One male sings, a 

 neighbor sings, the first repeats its song, and so on until most males 

 are echoing the song. The male often sings as he advances to drive 

 an intruder out of his territory. It also serves as a call or answer 

 to his mate as will be described below. 



What might be considered another variation of the song is actually 

 a distinct call. It is similar to the song in quality, intensity, and 

 pitch, but all the notes of the series are given with the same rhythm, 

 so that it does not end in a trill. As compared with the song, it 

 might be written as pit — pit — pit — pit — pit — pit — pit. The number 

 of notes in the series is usually 7 or 8 but may be only 2 or more 

 than 15. The individual notes are sometimes more a peeka, pita, or 

 peet, and the intensity is more variable than that of the full song. 

 This call is used mainly by the female but is also used by the male 

 and is a call to the mate. Innumerable times I have heard the full 

 song given first and answered by this one, or the reverse is just 

 as frequent. Often the calls alternate three to six times, or they may 

 even be given simultaneously. Such calls and answers may be heard 

 at any time of day and throughout the year and seem to give the 

 location of one to the other, as one of the birds frequently goes to the 

 other. Sexual excitement may also play a part as variations of these 

 calls, variously recorded during field work as pit-tr-tr-tr-tr, 

 perrrrrrrrt, musical repeated trrrr or weak pit followed by accented 

 trrrrr, are heard on the days when the pair is completing a nest 

 and sexual flight or copulation is taking place, though neither of 

 these acts is invariably accompanied by this song. 



Sometimes the response to the loud-ringing call of either the male 

 or female is a faint burring note, hrrrrrr. This short note is given 

 at intervals as a pair forages and seems to keep the two near together. 



A similar but louder accented krrrr, often repeated three or four 

 times, is an alarm note. It is given as the bird disappears in the 

 brush when it is startled. It is often given by a trapped bird or 

 by another bird that is circling the trap. 



A loud continuous Jcrrrr that may be kept up for minutes on end is 

 a scolding or mobbing note. At intervals it may be interrupted, only 

 to start again with equal vigor. The bill is held slightly open, and 

 the whole body vibrates as the sound is produced. The bird is in 

 constant motion, shifting from one perch to another and following or 

 circling the disturbing factor, usually a jay. The same note was used 

 to mob a sharp-shinned hawk. Once a snake appeared to be the cause. 

 The same sound was often given when I was near the nest. 



