In Mendocino County now; Humboldt is up next

Posted by Brian on April 6, 2017 at 10:15 PM

When it rains in southern California, it usually stops after a short while. When it rains in Mendocino, it doesn’t seem to have an end. At least there’s time for an update! I’ve traveled from San Diego, to Los Angeles, Santa Barbara, San Luis Obispo, Monterey, and now Mendocino. Next up (hopefully by the end of the weekend!) will be Humboldt County. It’s beautiful out here. Freezing, but beautiful. Tons of pine trees, dense forest, and riparian areas to aid the transition from forest to ocean. Also, I can’t forget the invasive Himalayan Blackberry (Rubus armeniacus) and it’s painful thorns. However, the hummingbirds love it. The campground I’ve been staying in at MacKerricher State Park, is my favorite of the trip. Towering pine trees, lots of separation between campsites, the sound of the ocean, peace and quiet after dark, and rain pattering the tent throughout the night. Nothing better than that.

I'm pretty excited to get into Humboldt County, because earlier in the year I made a model based on rainfall and temperature data predicting the hybrid zone would begin there. It has consistently aligned with the localities and divisions of the hybrid zone I've sampled thus far (divisions include pure Rufous Hummingbird populations, Rufous-like hybrids, 50/50, Allen's-like hybrids, and pure Allen's Hummingbird populations), so I am hopeful. Humboldt County would comprise the beginning of the Allen's-like part of the hybrid zone. If so, it might highlight the relationship between the climate and these two species, the types of habitats they are able to hybridize in, and the habitats and conditions they are dependent upon. Basically, Rufous Hummingbird requires wetter, colder, habitat than Allen's Hummingbird.

Rufous Hummingbird are still migrating, and they often make things very confusing when I’m trying to track and capture breeding Allen’s Hummingbird. Outside of courtship behavior, it’s very difficult to tell the two species apart. Often (but not always), the back of Rufous Hummingbird males is relatively close to being 100% orange in color, while the back color of Allen’s Hummingbird males is usually 60-100% green. Other than that, unless you have a bird in your hand, or they are performing courtship displays, good luck telling them apart. Females are even more difficult to differentiate, and have to be “in the hand”. There are a lot of Rufous passing through here, and several of them are displaying, which might seem strange considering they haven’t yet arrived at their breeding grounds. They just have a little trouble holding in their…excitement. This morning I watched a male Rufous Hummingbird perform a really long shuttle display (which is a close quarters courtship display that can also be used as a form of aggression) to a White-crowned Sparrow (Zonotrichia leucophrys) who was probably a little puzzled.

How often do you think a hummingbird beats it’s wings per second? Some can beat their wings well beyond 50 times in a second! Everyone knows they’re exceptional performers in flight with the ability to hover, but they can also fly backwards with ease (watch a video here). Did you know the Ruby-throated Hummingbird (Archilochus colubris), found in the eastern United States, has a metabolic rate nearly 100 times that of an elephant? If you have a feeder up at home, you might notice the same hummingbird visit several times a day, and probably even more often than you think. This is because of their high metabolic rates and the fact that they burn so many calories so quickly. Some hummingbirds consume up to three times their bodyweight in nectar and insects per day!

That's all I've got for now. See you all soon!

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