Cassins’ In the House! (or nest boxes)

This morning we had our 15 day check on the four hundred and two Cassin’s Auklet boxes around the island. We found fourteen birds (and 2 cold, but fresh eggs). That’s good news because this means that next 15 day check we’ll probably get 200 of them. However, I will be on my break and will be unable to partake in the Cassin-Fest. Bollocks.

But anyway, it was a joy to be able to handle the Cassin’s today. It was my first time holding a seabird, and it barely fit in my hands in bander’s grip. They’re a lot more hefty and dumpy than the passerines I’m used to. Also when manhandled, birds shit. Oh yes. And bigger birds mean well… more poop, running down my jacket and pants. Always aim their bottom away!

 Here’s a photo of Pete holding a Cassin’s.

Whenever we see a bird in box, we first determine if it has an egg, by gently prodding it with the rubber end of our pencil. After that, we grab hold of the bird and pull it out to determine if it is a banded bird. Banded birds, have little metal rings around their legs with ID numbers on them.

If they are a known-age bird (that is based on the band, we know how old they are) we measure their wing chord, bill width and weigh them. P1030708

Measuring their bill width helps with determining their sex because males have marginally thicker bills. Unlike land birds, seabirds take turns incubating. Female one day, males the next. As Alex says, “Non sexist birds!”

We also always check if the egg is fine and not cracked by us or the Cassin’s when we reach in to grab it. If it is a known age birds we also take the width and length of the egg. Instead of closing down on the egg with the calipers, we open it smaller than the egg’s actual length, and gently widen it over to egg to prevent crushing accidents.


Cassin’s are quite the cuties. They unfortunately also make easy prey for the burrowing owls peregrine falcons and western gulls. It was a sight when a WEGU (western gull) ate a Cassin’s body whole today. It was like watching a sped up video of a snake swallowing prey. Big Gulp. These WEGUs will swallow anything. Apparently one of them was found dead on the coast, choked by a kielbasa. So much for table manners.


2 thoughts on “Cassins’ In the House! (or nest boxes)

  1. you’re turning into a right gerald durrell. sure you’re not squirreling away eggs to start your home menagerie when on break???

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