March 1st, 2006 by: cheyenne

We stopped at Isla Isabella en route from Mazatlan to San Blas. Isabella is a bird sanctuary chock full of blue-footed boobies, brown boobies, and frigate birds. And some other cackling gull whose name I can’t remember (sorry!). We lucked out in that all three birds happened to be breeding when we visited; only the brown boobies breed year round.

The island is very small and there are paths all over it where you can walk through brown/blue booby breeding areas (they just nest on the ground), then through the trees where the frigate birds nest. You end up walking very close to the birds (it’s unavoidable) and it’s pretty amazing. They are not afraid of mammals and just regard you with irritation when you wander around; they don’t fly away when you approach them. We took a lot of photos.

Isla Isabella, Mexico

Blue Footed Booby Walking, Isla Isabella, Mexico

Blue-footed booby. The feet really are blue.

Blue Footed Boobies nesting with chick, Isla Isabella, Mexico

Blue-footed booby family unit. Awwwww cute babies!!! These guys are pretty tiny; they grow nearly full-sized before the fluff starts to be replaced by mature feathers. The female booby makes a bleating sound that sounds like a cross between a toy trumpet and a kazoo and the male makes a hoarse cry that sounds like he’s been ‘debarked.’ They bleat/gasp at you when you get within 5-10 feet of the nest. Which is sometimes in the middle of the trail. Sheesh!

Blue Footed Booby Sky Pointing, Isla Isabella, Mexico

I think it’s pretty obvious what’s going on here. That’s the male sticking his arse in the air (he makes a hoarse exhale/cry when he does this). We spoke with one of the ornithologists on the island and he called it “sky-pointing;” it is a mating display, among other things. The female is regarding him with some indifference.

Blue Footed Boobies Courting, Isla Isabella, Mexico

Awwww! Booby love. This happened right after the mating display above. We sat around for a bit thinking we might get to observe some booby action but this is about as far as things went.

Blue Footed Booby Perched, Isla Isabella, Mexico

Male brown booby. They have chartreuse-colored feet and are really cute. All the boobies have great expressions but my favorites were the brown boobies.

Female Brown Booby, Isla Isabella, Mexico

Female brown booby. Cute! Cute!

Male Brown Booby, Isla Isabella, Mexico

Close up of a male brown booby. Interestingly, the brown boobies lay two eggs and when they hatch, the dominant baby kills the weaker baby. So the brown boobies end up raising only one baby. The blue-footed booby babies also do this but only if resources are scarce. I think we saw most blue-footed nests with both babies. However, even with two babies, one remains the dominant baby and probably gets the majority of the snacks.

Marine Iguanas, Isla Isabella, Mexico

Marine iguanas. When you walk through the trees, they tend to stay very still until you get to within a certain distance, whereupon they can’t stand it anymore and explode off into the brush.

Frigate Birds Flying, Isla Isabella, Mexico

Many circling frigate birds. They make very primeval clicking and shrieking sounds. It was kind of creepy winding through the trees, which form a sort of short canopy and the path is more like a tunnel. There are zillions of frigate birds above you at all times.

Frigate Birds Nesting with Chicks, Isla Isabella, Mexico

Frigate baby! Frigate birds have only one egg at a time.

Frigate brids showing red sacks, Isla Isabella, Mexico

The male frigate has a red sack that he blows up. They just hang around with all their necks ballooned out like this too. Looks pretty goofy.

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Cheyenne Weil, Joshua Coxwell