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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.
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Posts about Bird biology
Pelicans on the Gulf
Posted by: Jim Williams Updated: December 15, 2012 - 5:05 PM
Two of the Minnesota pelicans radio tagged this fall so their movements can be tracked are at wintering territory on the Gulf of Mexico.
Four American White Pelicans are sending signals to a research team. The study is intended to provide information on where on the Gulf the birds spend the winter, their migration paths, and their movements in Minnesota.
Impetus for the study was evidence of oil and oil dispersant chemical found last summer in eggs and bodies of pelicans nesting here. About one-third of the world population of this bird nests in Minnesota.
One of the tagged pelicans arrived east of the mouth of the Mississippi River in mid-October. Its radio signal is spasmodic, the most recent reception in late November.
A second bird arrived on the Gulf in mid-November. It was located south of Lake Charles, Louisiana.
Two birds are taking more leisurely trips. One of them flew 175 miles on Thanksgiving to a location on the Arkansas River. The second pelican moved through central Mississippi in late November, the last signal showing it near Greenwood, Mississippi.
The project is a partnership between Audubon Minnesota, the Minnesota Department of Natural Resources Non-game Program, and North Dakota State University.
To see the map and follow the pelicans go to http://mn.aOneudubon.org/
Early birds
Posted by: Jim Williams Updated: December 11, 2012 - 7:50 PMYesterday, cardinals appeared at our feeders at the exact time the sun set, making me wonder just how precise these birds can be, favoring twilight for afternoon feeding and hitting it perfect. Today the sun set at 4:32 p.m. The first cardinals arrived at 4:09. Precision isn't everything.
Birds look better in snow
Posted by: Jim Williams Updated: December 10, 2012 - 9:27 PMCardinals came to our feeders in force as soon as the snow stopped. We had 10 here Sunday at dusk. Monday, the count was eight. Cardinals feed in the dim light of dawn and the fading twilight at the end of the afternoon. Most other bird species retire earlier and rise later. Sunset Monday was at 4:32 p.m. The first cardinal flew into the yard at 4:32 p.m. I'm curious to know if that was a coincidence or if the birds' sense of light level is that keen. I'll try to time them for the next few afternoons.
The smaller lakes near our home were nearly 100 percent ice-coveredMonday. A few small open spots of water remained. I was checking for ducks and coots -- and eagles. If waterfowl can be found on small patches of open water, you might find eagles, too. The hunting is good when the ducks are in restricted space. Coots become particularly vulnerable because they must run across the water to get to lift-off speed. I saw a pair of immature Bald Eagles at Mooney Lake in western Plymouth. There was no prey there, though. With cold, windless nights certain bays on Lake Minnetonka might be good places to look for eagles. The requisite coots are on Smith's Bay, west of Wayzata, but most of that lake is open, at least from the bay out as far as I could see, excluding some narrow bands of ice along the shore. No eagles there today, but a grandson and I watched an eagle make lazy passes at those coots on Saturday. The road there, County 15, is bad at the best of times, narrow, twisty, and busy. Walking on the shoulder -- well, right now there is no shoulder. Parking away from 15 is possible, leaving one with no more than a quarter-mile walk. Four Whooping Swans were on the bay today. They don't worry about eagles.
In the crab apple orchard I check for waxwings and grosbeaks -- nope -- I found more robins on Monday. Forty or 50 of them were picking apples. One photo below shows the effort the birds sometimes make to pull the apples from the tree. The other photos show a robin in the picking process. At the height of the pull the nictitating membranes found in bird eyes have pulled over the pupil. This is a third eyelid, moving across the eye at right angles to the regular eyelids, between them and the eye surface. This membrane moistens and cleans the eye, and provides protection.
Nesting habits, neat and messy
Posted by: Jim Williams Updated: December 2, 2012 - 12:38 PMJust finished cleaning the nest boxes I manage at a golf course near our home. There are 40 boxes on the trail. Use splits about 50/50 between Tree Swallows and Eastern Bluebirds. House Wrens and Black-capped Chickadees use a handful of the boxes.
Bluebirds boxes are simple to clean: just pull the neat, unsullied grass nest from the box. Chickadee nests are made of moss, tightly fitted to the dimensions of the box base. They come out intact, and clean. Wrens weave sticks into hollow forms that fill boxes. Sometimes I can slide nest out of the box intact. I get to marvel at this piece of intricate engineering. Wren nests also are clean.
Clean means no feces in the nest. Bluebirds, chickadees, wrens, most songbirds keep a clean house by removal of chick feces in a most ingenious way. The chick packages its waste in a strong membrane that is produced upon the little bird being fed. This is called the fecal sac. The parent bird brings food and leaves with the sac.
Which brings us to Tree Swallows.
Tree Swallows remain in the nest for as much as a week longer than, say, bluebirds. Bluebirds fledge in 13 or 14 days, swallows in about 20. Swallows produce fecal sacs for all but the final five days or so. As they near fledging, the sac mechanism slows up and quits. The swallows then just relieve themselves where they sit.
A used Tree Swallow nest is a nasty thing. The grass and feathers used as construction material, when mixed with feces, become bricks. They stick to the box. I pry them out.
Violet-green Swallows, the western version of our Tree Swallow, have evolved to what I consider a more advanced state. When their fecal-sac mechanism gives out they point their tails to the corners of the nest (or box) when the need arises. The nest stays relatively clean.
So what is it about the evolution of these two closely related species that produces different approaches to the same problem?
Below, a fresh Tree Swallow nest. I have no photos of the post-nesting mess.
Pelicans arriving at Gulf
Posted by: Jim Williams Updated: November 26, 2012 - 2:48 PMTwo of the Minnesota pelicans radio tagged this fall so their movements can be tracked have arrived at their wintering territories on the Gulf of Mexico.
Four American White Pelicans are sending signals to a research team. The study is intended to provide information on where on the Gulf the birds spend the winter, their migration paths, and their movements in Minnesota when they return in the spring.
Impetus for the study was evidence of oil and oil dispersant chemical found last summer in eggs and bodies of pelicans nesting here. About one-third of the world population of this bird nests in Minnesota.
One of the tagged pelicans arrived east of the mouth of the Mississippi River in mid-October. Its radio signal is spasmodic, but one reading did arrived on Nov. 21.
A second bird arrived on the Gulf Nov. 14. It is located south of Lake Charles, Louisiana.
Two birds are taking more leisurely trips. One of them flew 175 miles on Thanksgiving to a location on the Arkansas River. The second pelican moved through central Mississippi this weekend, the last signal showing it near Greenwood, Mississippi.
The project is a partnership between Audubon Minnesota, the Minnesota Department of Natural Resources Non-game Program, and North Dakota State University.
To see the map and follow the pelicans go to http://mn.aOneudubon.org/
Below, American White Pelicans
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recent posts
- Our Christmas star
- Adding insult to injury
- Eagle attacks child -- not!
- A redpoll winter
- On becoming a better birder
- Bird Watcher's Bible -- a complete treasure
- Pelicans on the Gulf
- Early birds
- Birds look better in snow
- Water!
- Nesting habits, neat and messy
- Greenland's melting ice
- Finally, Bohemian Waxwings
- Pelicans arriving at Gulf
- Grosbeaks and redpolls
- Tufted Titmouse and winter finches
- Watch the wind
- Winter birds
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