Jim Williams has been watching birds and writing about their antics since before "Gilligan's Island" went into reruns. Join him for his unique insights, his everyday adventures and an open conversation about the birds in your back yard and beyond.

Posts about Bird biology

Goldfinches showing the color of spring

Posted by: Jim Williams Updated: March 25, 2015 - 11:21 AM

If doesn't look a lot like spring today -- Wednesday -- unless you are looking at male American Goldfinches molting from their drap winter plumage into the bright yellow of spring and summer.

World Sparrow Day: we missed it

Posted by: Jim Williams Updated: March 22, 2015 - 2:27 PM

Saturday last was World Sparrow Day. You probably missed it. I found out a day late. 

The sparrow being honored was the House Sparrow, one of more than 40 species in that family. House Sparrows generally are ignored by birders unless as a check mark on a list. House Sparrows deserve recognition, and even concern, for a couple of good reasons. And I say this as someone who has pulled sparrow nests from my bluebird nest boxes, then killed those intruders. (I think in the future I will work to simply keep them at bay.)

What’s the big deal? As was pointed out by more than one commenter on the email list BirdChat, House Sparrows, along with pigeons, are many people’s only contact with birds. House Sparrows are bird ambassadors in the city, particularly in its inner parts. Without House Sparrows, many city residents have less contact with wild animals than they already do; such contact can be almost nil.

Second, in Great Britain, from which our sparrows were brought in the 1800s, this species is on a steep decline. There was a loss of 71 percent of the estimated population from 1977 to 2008. No one knows why this is happening. This is scary. What is the cause of  the loss? What species birds are next? Is this an indication of our future, of an environment headed in such a direction that now House Sparrows are having survival problems? (I know, that's alarmist. The small chance is distant and remote and small, right? Then there is the canary in the coal mine.)

House Sparrows are tough. They have been recorded as living in coal mines in Great Britain, and breeding high on mountains. They are the most human-adapted bird species on earth. If we can’t keep the planet hospitable for them, what then?

House Sparrows, male above, female below. They're really rather handsome birds.

More on weasels (and a bit on shrews)

Posted by: Jim Williams Updated: March 10, 2015 - 11:17 AM

Several days ago we posted a story about a weasel in England that jumped a woodpecker, and soon found itself airborne aboard the bird’s back.

 

Weasels are very interesting animals. Almost every Google discovery uses the word vicious to describe them. There is another attack story from England, this time a weasel attacking a squirrel. Rabbits and pigeons also are prey. Weasels think big.

 

We have or had a weasel living here, seen in our yard last summer, but unfortunately it has not made a dent in the squirrel population. 

 

A Wisconsin web site lists weasels with badgers and wolverines when it comes top contenders for North America’s toughest mammal predators.  A couple of web sites list weasel as the smallest carnivore in North America. Not true. The short-tailed shrew has that honor. It is smaller than most mice, with a metabolism running full-tilt all of the time. The heart rate of a shrew at rest has been recorded at 750 beats per minute. It must eat prey equal to its own weight every day. 

 

Some years ago, in a rented garage, I had a rat problem. I set out a large wooden snap trap. It caught a mouse. I ignored it on first sight, coming back later to reset the trap. It was nowhere to be seen. I also had short-tailed shrews (sort of like a zoo, that garage). I found the trap under a cupboard, nothing remaining of the mouse but a shred of skin. I’m certain that a shrew, tiny little guy with that huge appetite, dragged the trap into that dark crevice to eat in private. The trap had to weigh 50 or 60 times as much as that tiny shrew, maybe more. I’ll bet a shrew could eat a weasel in the right circumstances (maybe after it fell from a flying woodpecker). 

 

Short-tailed shrews can be identified by the darkened tips of their front teeth. This shrew species also is one of the world’s few poisonous mammals, injecting prey when its bites.

 

That woodpecker was lucky its attacker was only a weasel.

Minnesota woodcock migration tracked

Posted by: Jim Williams Updated: March 8, 2015 - 10:03 PM

Three American Woodcock captured at Sherburne National Wildlife Refuge last fall are playing a major role in a project aimed at tracking the birds’ migratory moves. The three are among several woodcock carrying tiny solar-powered satellite transmitters that mark locations every 48 hours.

 

You can follow the birds’ movements both on wintering grounds and as they begin spring migration back to Minnesota. (That should be underway very soon.) Go to http://www.ruffedgrousesociety.org/woodcockmigration.

 

One of the birds was in southern Arkansas yesterday, Sunday, March 8, moving north from Louisiana, where it had spent most of the winter. A second bird was in western Arkansas, near the Oklahoma border. It, too, had moved north from Louisiana. The third bird was in northwestern Mississippi on March 4. On the maps, click on the colored dots to find and track the birds.

 

Project sponsors — multiple organizations including the Minnesota Department of Natural Resources — plan to have 45 birds carrying transmitters a year from now.

 

The transmitters are similar to those being used to follow migration of Purple Martins from nesting locations in North Dakota. The transmitters placed on Snowy Owls during the 2013-14 winter, including a bird that over-wintered here, are similar, but download information via cell-phone towers.

 

The transmitters on the woodcock must be recovered for the information to be secured.

 

This has nothing to do with the tracking project, but below is a photo of a woodcock head and bill. I found this last spring at a location where the birds had been preforming courtship displays. I’ve no idea how the bird lost its head. 

 

I found the bill interesting. The lower third of the bill contains sensitive nerve endings that help the bird locate earthworms, a major food item. Look closely for the tiny holes that I believe aid in prey location. The tip of the upper mandible can be opened while the bill is underground, allowing the bird to grasp worms and pull them from the ground. The bird’s tongue and the underside of the mandible are rough-surfaced to provide a good grip. The bird then sucks the worm into its bill.

 

Woodcock return to Minnesota from now through early May, with mid-April a migration peak. Warmer weather could advance the later dates. 

 

 

 

 

 

Heron swallows a large carp

Posted by: Jim Williams Updated: January 30, 2015 - 3:20 PM

A couple of years ago at Lake Independence in western Hennepin County I watched a Great Egret catch and swallow a panfish as large as my hand with fingers spread. The bird had to work at it, mostly to position the fish so it went down headfirst, the best, probably the only way to swallow something with fins. Here is the photo I took, plus a second of an egret with its slender neck as usuallly seen. I mention this because of a video recently posted of a Great Blue Heron swallowing a carp, a huge carp that probably weighed more than the bird. It's available on YouTube (where else?). The link is http://bit.ly/1xsFmvn

There is a collection of birds-swallowing-large-fish at that site. I did not see any of the birds flying away after those huge meals.

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