Category Archives: Bird Behavior

Sheltering From The Storm

Bird Behavior, Weather & Sky
Immature Cooper’s hawk sheltering in a garage in Boca Raton, 2 Sep 2019, 3:44pm (photo by Natalie Mitchell)

As Hurricane Dorian approached Florida on Labor Day afternoon and a storm band dowsed the area with wind and rain, my sister-in-law went into her garage in Boca Raton and found a bird, 15-18″ tall, perched high near the ceiling. She texted me a photo. “What is it?”

This immature Cooper’s hawk is too young to have seen a hurricane before, but he knows that the weather is bad and he can feel it’s going to get worse. If he’s a skillful hunter he’s already eaten a lot in anticipation of the storm and just needs a safe place to wait out the weather, so he picked the best available option. He came indoors.

Cooper’s hawks don’t breed in South Florida but they spend the winter there (see range map). This youngster arrived recently and is improvising in bad weather. So far so good.

Cooper’s hawk range map from Wikimedia Commons (orange=breeding, purple = all year, blue=winter)

The bird may have to wait in the garage for a while. Hurricane Dorian could take 24 hours to move out of the area.

When the storm is over this bird will be glad to leave.

UPDATE, 3 Sep 2019, 8a: The storm isn’t bad in Boca Raton. The hawk left.

(photo by Natalie Mitchell, range map from Wikimedia Commons)

Beaks Built For Fighting

Bird Anatomy, Bird Behavior
Lesser violetear (green) confronts a sparkling violetear (photo by Julian Londono via Wikimedia Commons)

For centuries scientists have assumed that hummingbird beaks are always shaped for the flowers they feed on, but a recent study of their nectar-feeding mechanisms produced a surprising result. Some male hummingbirds have beaks that are inefficient for feeding but great for fighting.

Alejandro Rico-Guevara, an evolutionary biologist at UC Berkeley, assembled a team to study the biomechanics of nectar drinking. Using high-speed cameras they watched the entire feeding apparatus including bill shape, tongue shape, fluid trapping and elastic pumping.

Surprisingly, they found that male beak shapes in several South American species make it harder for males to draw in nectar. The females have nectar beaks but the males have straight dagger beaks or backwards facing teeth and hooked tips. You can see some of these features on the male tooth-billed hummingbird (Androdon aequatorialis) below.

Tooth-billed hummingbird (photo by Andres M. Cuervo via Wikimedia Commons)

Among these species the females don’t fight much but the males are extremely belligerent. Examples include the tooth-billed hummingbird (Androdon aequatorialis) above, and the sparkling violetear (Colibri coruscans) and saw-billed hermit (Ramphodon naevius) below.

Sparkling violetear looks threatening (photo from Wikimedia Commons)
Saw-billed hermit (photo from Wikimedia Commons)

This video from the UC Berkeley study shows what those beaks are really used for!

For more details see this article at Gizmodo and the study itself at Oxford Academic.

(photos from Wikimedia Commons; click on the captions to see the originals. video from UC Berkeley Research)

Blue Jay Fools A Young’un

Bird Behavior, Songbirds

Like other members of the Corvid family, blue jays (Cyanocitta cristata) are very intelligent and have strong family ties. Some of their intelligence and social awareness is put to use to fool each other, especially where food is involved.

Watch the video above by Lesley The Bird Nerd to see how an adult blue jay played a trick on a young one that was planning to steal his food.

(video by LesleyTheBirdNerd on YouTube. Click here for her YouTube site.)

Prankster on Camera

Bird Behavior, Vocalizations

Last week Colin Roberts tweeted this video from one of his forest trailcams in southwest Scotland. His cameras record the activities of pine martens but the view is sometimes dominated by another species, the Eurasian jay.

Eurasian jay (photo by Pierre Dalous via Wikimedia Commons)
Eurasian jay (photo by Pierre Dalous via Wikimedia Commons)

Eurasian jays (Garrulus glandarius) are intelligent, curious, and very vocal mimics. This particular jay punctuates his visits with the sounds of a squeaky tree, a tawny owl, and an amazing Star Wars riff.

Then he gets really close to the lens and … oh my!

(tweet and video by Colin Roberts @PinetenColin, photo from Wikimedia Commons)

Graceful Predator

Alaska, Bird Behavior, Birds of Prey, Travel
Long-tailed jaegar in flight (photo by Gregory “Slobirdr” Smith, Creative Commons license on Flickr)

If I had to pick a Best Bird on my trip to Alaska it would be the long-tailed jaegar (long-tailed skua, Stercorarius longicaudus), the most graceful arctic predator.

Long-tailed jaegars are the smallest of skuas, a genus of predatory seabirds that range from pole to pole. In flight their long tails and flowing movements remind me of swallow-tailed kites as they float over the tundra in pairs and loudly defend their territories. On the hunt they can hover like kestrels, as shown in the video below.

Though long-tailed jaegars are seabirds, their favorite foods in Alaska are collared lemmings.

Illustrations of Nelson’s collared lemming and Ungava collared lemming at burrow (from Wikimedia Commons)

How does a seabird without talons capture rodents? Well, he doesn’t use his feet.

Long-tailed skua calling (photo by Allan Hopkins, Creative Commons license on Flickr)

Birds of North America Online explains his hunting technique …

Long-tailed Jaeger hunts these lemmings by hovering or poising in a headwind at height of 1-10 m [3-30 feet] (usually about 4 m) above tundra, like a kestrel unlike other jaegers, and by watching from perches on small rises or frost mounds … Having detected prey, often pursues it on foot and pecks it until it is dead; never uses feet to capture prey.

Birds of North America Online

Though both sexes can incubate, the male long-tailed jaegar spends two thirds of his time hunting for his mate while she warms the eggs.

Long-tailed jaegar on nest (photo from Wikimedia Commons)

We could see her white chest far away on the tundra, waiting for her graceful mate to come home.

(photos by Gregory “Slobirdr” Smith, Allan Hopkins and from Wikimedia Commons. Click on the captions to see the originals.)

Taking Out The Garbage

Bird Anatomy, Bird Behavior, Nesting & Courtship
Western bluebird carrying fecal sac away from the nest (photo from Wikimedia Commons)

Nests look like safe havens for baby birds but if they’re not kept clean they can quickly become infested with pathogens and parasites, or their smell can attract predators. For songbirds it’s especially important to keep their nests clean. Fortunately their bodies have evolved to make this easy.

In the photo above, a western bluebird is taking out the garbage after visiting his nest. In his beak is a fecal sac, a package of white mucous membrane surrounding the feces of one of his nestlings. Every nestling produces a fecal sac shortly after eating. The packaging makes it easy to keep the nest clean.

What the parents do with the fecal sacs depends on the species. Most drop them far away from the nest but some species, such as American robins, consume the fecal sacs while the nestlings are quite young and carry the sacs away when the nestlings are older.

Just before songbirds fledge their bodies switch from producing fecal sacs to defecating wet feces over the edge of the nest. Robins’ nests don’t have whitewash beneath them until you can see the youngsters above the nest rim. By the time they are messy, baby robins are almost out of there.

Birds of prey aren’t as fastidious. If you watch peregrine and bald eagle nestcams, you’ll see two differences in their nest sanitation:

  1. Raptor nestlings don’t produce fecal sacs. Instead they back up to the edge and aim wet feces away from the nest.
  2. As the nestlings age the parents become lazy housekeepers, often leaving food debris at the nest as a self serve snack for the young.

Birds of prey aren’t worried that predators will smell their nests. That’s why they don’t always take out the garbage.

(photo from Wikimedia Commons; click on the caption to see the original)

Gifts From Crows

Bird Behavior, Crows & Ravens

Four years ago in Seattle, eight year old Gabi Mann consistently fed and interacted with the crows in her backyard. She formed such a tight bond that she could recognize individual crows by sight and gave them names. The crows rewarded her by bringing gifts.

Many animals give gifts to members of their own species but crows and other corvids are the only ones known to give gifts to humans. As John Marzluff explains in the video, crows will do this for people who feed them a lot and pay attention to them, or even rescue them.

When I read about this several years ago in Marzluff’s book Gifts of the Crow, I briefly thought about trying to make friends with crows but decided it would be a difficult relationship. If your friendship with crows is based on food they remember your generosity and bring their friends. Lots of friends. They can be quite demanding and don’t understand if you stop. Not everyone appreciates this.

Gabi’s story made international news in February 2015 but we don’t hear about it anymore. Six months after this video was filmed two of Gabi’s neighbors sued, demanding $200,000 and a court order prohibiting the Mann family from putting out more than a 1/4 pound of bird food. It took a year to settle the lawsuit; the details were not made public.

Crows remember the faces of those who are mean to them and those who are especially kind. I’m sure that a few special crows remember Gabi.

(video from BBC on YouTube)

Brazen In Winter

Bird Behavior, Songbirds
Northern mockingbird blocks a northern cardinal (photo by Marge Van Tassel)

This week I wrote about northern mockingbirds having knock-down drag-out fights during the breeding season. Did you know that mockingbirds are also territorial in the winter? Even though they’ve migrated far from their breeding territory they vigorously defend their wintering zone.

Last winter Marge Van Tassel had a pushy mockingbird in her Armstrong County yard. She sent this photo saying, “The male of the pair in our yard chased all birds away from the food bowl last year when he was in it. He even chased this female cardinal back to a bush.”

Yikes! She’s putting on the brakes with her tail.

Mockingbirds are brazen, even in winter.

(photo by Marge Van Tassel)

The More The Merrier

Bird Behavior, Songbirds
Eurasian tree sparrow, great tit and blue tit at a feeder in Bulgaria (photo from Wikimedia Commons)

Squirrels eventually figure out a puzzling bird feeder, but have you ever noticed that birds do too? Lone songbirds usually can’t do it, but scientists have proven that a flock can. The bigger the flock the better.

I learned this years ago when I set up a “goldfinch-only” thistle feeder whose holes forced birds to perch upside down to eat the seeds. This is easy for American goldfinches but not for the birds I meant to foil — house sparrows. Lone house sparrows gave up on this feeder but the flock tried a lot of methods. A few of them would land right-side up and slowly fall forward until they were upside down. One of them put out his wing to grab the feeder. The rest of the flock followed.

On Throw Back Thursday, learn how songbird flocks can solve puzzles faster than individuals in this vintage article: Two Heads Are Better Than One.

The more birds at our feeders the merrier we are … and so are they.

(photo from Wikimedia Commons; click on the caption to see the original)