Tufted Titmouse Breeding Behavior

THIS study of the Tufted Titmouse (Parus bicolor) is based mainly on data from 130 birds color-banded from 1944 through 1968 in suburban Baltimore, Maryland, and on three nestings, none entirely successful, in a box at my home. Many observations were made at my window feeding shelf. Already documented for this species are sedentariness (Van Tyne, 1948; Laskey, 1957), permanence of mating (Van Tyne, 1948), incubation and brooding by the female alone and care of young by both parents (Laskey, 1957), all of which I have also observed. This paper elaborates on some of those topics, but concentrates on gaps in the species' life history. Comparisons of behavior are made with other crested species of American titmice. Sexual dominance.-The male Tufted Titmouse shows dominance over his mate throughout the year; females show subordination to other males as well. At all seasons paired birds are commonly on my 20-inch-square feeding shelf together. Yet I have a number of records of males coming while their mates were present and them about, or them away entirely and sometimes following. I also once saw a male fly at his mate in a bush and drive her several yards. I have records of four pairs: three observations on one pair (24, 25 March, 7 April) and five on another (23, 26 October, 11, 19 November, 20 January) that had not yet nested; one (27 May) on a pair that had nested the preceding year, and another (13 June) on a pair with young just out of the nest. Dr. Keith L. Dixon (in litt.) has seen similar driving of the female Plain Titmouse (P. inornatus) in the prenesting period. Females also subordinate themselves on the feeder to their mates and to other males. On a 2 January one quivered her wings, uttered a zkee-zheezhee and fled when her mate of a year's standing came. When I use a 6-inch-wide pull-string trap on the shelf this subordination becomes striking. For example while a male was opening a seed on the shelf rim one 15 October, his mate came and entered the trap. Before she had chosen a seed he entered for another and she went out empty-billed and waited until he had got his and flown, then she reentered and got hers. On a 21 June a different female did the same when a male not her mate came. Male dominance was shown, too, during the nestings I watched, as detailed below under Feeding of nestlings.