hummingbird torpor

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Beginning Birding: Hummingbird Class

Don’t you just love learning new things?  It’s especially fun when it’s something your passionate about.  We took a hummingbird class at the spectacular Los Gatos Birdwatcher.  This locally owned store describes themselves as

the nature lover’s general store, specializing in everything to do with bird feeding and bird watching.

If you’re local, or planning a visit to the area, it’s a must see. The owners and staff are wonderful people, knowledgeable and helpful in every way.  Their current dog in residence is a chocolate Cocker spaniel named Marley.

Lisa Myers of Let’s Go Birding presented the hummingbird class, then lead us on a two-hour field trip Saturday morning.  We had so much fun.  Lisa leads a variety of birding trips throughout the bay area.  She’s incredibly knowledgeable with a wonderful sense of humour.

Lisa Myers and Freddy Howell

Lisa Myers and Freddy Howell

We’ve been feeding hummingbirds in our garden for as long as I can remember. We have several feeders and hummingbird-attracting plants.

2014, 03-20

Hummingbirds in our garden

I’ve read a number of books and articles over the years, but still found much to learn.  It’s also nice spending time with a group of  like-minded folks.

Here are a few things I didn’t know:

  • There are over 300 species of hummingbirds, but only six or seven in the Bay Area.
  • Hummingbirds are native to the Americas.  They’re not found anywhere else in the world.
  • Yellow attracts bees, red attracts hummingbirds.  Therefore a hummingbird feeder with yellow plastic ‘flowers’ sends out mixed messages.
  • Anna’s Hummingbirds, native to our area, live here year round. There is no need to remove feeders during the colder months.
  • Hummingbirds are the only bird that can hover in the air, as well as fly forward and backward.
Anna's hummingbird

Anna’s Hummingbird

It was fascinating learning about torpor. Hummingbirds enter this state of hibernation nightly to conserve energy.  I found the following explanation at ScienceBlogs™

Even sleeping hummingbirds have huge metabolic demands that must be met simply to survive the night when they cannot forage. To meet this energetic challenge, hummingbirds save enough energy to survive cold nights by lowering their internal thermostat at night, becoming hypothermic. This reduced physiological state is an evolutionary adaptation that is referred to as torpor.

Torpor is a type of deep sleep where an animal lowers its metabolic rate by as much as 95%. By doing so, a torpid hummingbird consumes up to 50 times less energy when torpid than when awake. This lowered metabolic rate also causes a cooled body temperature. A hummingbird’s night time body temperature is maintained at a hypothermic threshold that is barely sufficient to maintain life. This threshold is known as their set point and it is far below the normal daytime body temperature of 104°F or 40°C recorded for other similarly sized birds.

Isn’t that interesting?

Please be sure to check back tomorrow for news and pictures from our two-hour field trip to the Santa Clara Valley Audubon Society.

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