Food and food consumption of nestling tits, Parus major minor and Parus varius varius, in the ever-green broad leaved forests in northern Kyushu

Abstract

1) Feeding rate and food consumption of nestling tits, great tit and varied tit, were assessed by means of automatically photographing of foods brought to the nest, in the ever-green broad leaved forests in northern Kyushu.2) In the diet of great tit nestling, lepidopterous larvae formed about 70%, and moths, spiders and diprionid larvae are other important preys. Mean weight of prey is 87.0mg, dr. and preys weighed from 40 to 80mg. dr. were brought most frequently. In the varied tit nestling, lepidopterous larvae formed 45% and, alternatively, proportion of moths and spiders increased. Mean weight is 42.8mg. dr. and preys below 40mg. dr. were brought frequently.3) Feeding frequency of great tit was stable at about 13/nestling/day except that it was at about 21/nestling/day in the middle phase of nestling period. Varied tit often brought more than one prey at a time, 1.59 preys/visit on average. Feeding frequency of varied tit was stable at 14/nestling/day (22 preys/nestling/day) after 4th nestling-day, though it was somewhat lower just after hatching.4) Daily amount of foods just before fledging was 4.67g. fr./nestling/day and 29.0% of the nestling body weight of great tit. For varied tit, 3.16g. fr./nestling/day and 19.4%.5) Diet composition, feeding rate and food consumption are compared between several different habitats and between above two species, and was discussed.