Hummingbird identification

The WRMD data for hummingbird age were initially classified into two main categories: “nestling” and “adult-like bird” hummingbirds. All nestlings were considered unknown for sex and were classified into species groups (Selasphorus spp. and non-Selasphorus spp.) based on known breeding ranges and seasons of hummingbird species in California, and associated information reported by rescuers. The adult-like birds were further classified as “Selasphorus spp.” and “non-Selasphorus spp.” (Russell & Russell, 2001). Identification of adult males is less challenging for hummingbird species found in California due to their vibrant, distinct gorget colors compared to their counterpart adult females or young birds (Russell & Russell, 2001). For non-Selasphorus spp. (Anna’s Hummingbirds (ANHU), Black-Chinned Hummingbirds (BCHU) and Costa’s Hummingbirds (COHU)), records mentioning adult males were assigned “adult-like” and “male” for age and sex respectively. All other non-nestling and non-Selasphorus spp. hummingbirds were categorized as “unknown” and “female-like” for age and sex respectively. Similarly, for Selasphorus spp., records mentioning adult males (Allen’s Hummingbirds [ALHU] and Rufous Hummingbirds [RUHU]) were termed as “adult-like” and “male” for age and sex respectively. All other non-nestling Selasphorus spp. hummingbirds were considered “unknown” and “female-like” for age and sex. Lastly, records for hummingbirds without signalment information were categorized as “unknown” for age, sex, and species.