Los Farallones

Dispatches from Point Blue’s field station on the Farallon National Wildlife Refuge

Eggs, eggs everywhere: The Cassin’s

By | May 11, 2017

Cassin's Auklet

So… things are starting to get real on the Farallon Islands. Nearly all our seabird study species have started laying their first eggs!

First were the Cassin´s Auklets (Ptychoramphus aleuticus):

Nest boxes

Nest boxes

 

There are 446 regular nest boxes distributed all over the island and 32 nest boxes in a study site called the Habitat Sculpture. These boxes serve as a place for birds to lay their eggs and raise their young that we can monitor easily.

Claudia blocking the entrance to one of the Habitat Sculpture boxes

Claudia blocking the entrance to one of the Habitat Sculpture boxes

 

 

 

 

 

After a month of checking empty boxes, on April 13th we found our first Bird over Egg!

 

 

 

 

 

 

Many birds have a metal band on their right leg with a unique series of numbers. This helps us follow them throughout their lives and determine their timing of breeding, reproductive success, site and mate fidelity, and survivorship, among other population parameters. All of these factors can help us understand how these birds respond to changing ocean conditions.

We measure the bill depth and wing chord and weigh all banded Cassin´s Aucklet.

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During our last major Cassin´s Auklet check we found more than half of our boxes occupied already. It was a lot of work but everyone got to handle and process many individuals which proved to be exciting to all interns. Let´s see how many more continue to use our high quality nest boxes!

P.S. We have recently been seeing them breeding in crevices as well.

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