Ancient Murrelet vs Guadalupe Murrelet

In short

The Ancient Murrelet and Guadalupe Murrelet are both small seabirds of the genus Synthliboramphus, but they can be distinguished by their facial markings: the Guadalupe Murrelet has white extending in front of and often over the eye, unlike the Ancient Murrelet. Both species are similar in size and structure, making plumage details crucial for identification.

Identification tips

1. Look for the white facial markings on the Guadalupe Murrelet, which extend in front of and often over the eye. 2. Observe the overall size and shape, which are similar between the two species, focusing on plumage differences. 3. Consider the location: Ancient Murrelets are more widespread in the northern Pacific, while Guadalupe Murrelets are more localized.

Size

Both species are similar in size, typical of small auks, with no significant size difference to aid identification.

Plumage

The most reliable plumage difference is the facial markings: Guadalupe Murrelet has white extending in front of and often over the eye, while the Ancient Murrelet lacks this feature. Both have similar body coloration with dark upperparts and white underparts.

Behaviour

Both species rear their young at sea, a unique trait among seabirds, and are nocturnal at breeding colonies. Their foraging behavior is similar, focusing on small fish and zooplankton.

Habitat

Ancient Murrelets are found around the northern Pacific rim, from China to British Columbia, while Guadalupe Murrelets are more localized to the waters around Guadalupe Island. Both species forage offshore but can be seen near land where food is abundant.

Voice

Ancient Murrelets have a diverse vocal repertoire associated with nocturnal colony visits, but specific vocal differences with Guadalupe Murrelets are not detailed.