PHENOLOGY OF THE FIRST REPORTED CASE OF SAME-SEASON NEST REUSE IN ANNA’S HUMMINGBIRD

Abstract

Natural history observations of rare events can provide invaluable data about the range of variation in a trait or behavior. In birds, these fortuitous observations can help supplement scientific understanding of the timing and location of nesting behavior, events which are often difficult to observe. Reuse of cup nests is thought to be rare, but incidental reports document nest reuse both within and across breeding seasons. A chance instance of a female Anna’s Hummingbird (Calypte anna) initiating a nest on our balcony in California was an opportunity to make detailed observations of nesting phenology with photos and videos. After successful fledging of this first nest, the same female immediately initiated a second nesting attempt in the same nest. To our knowledge, this is the first documented case of a female Anna’s Hummingbird reusing a nest in the same season, and only the second case confirmed through direct observations in any hummingbird species.