Tuesday, April 6

Tree creatures

I got my river walk in this morning close to noon. Wind-whipped waters. A few Canadian geese still hanging around. Great huge sun-bleached cottonwood trees like beached creatures lying prone beside the river. Looking like great huge grey-almost white bones. I don't think the trees ever have been in the river but they could have been. They are old and are certainly in the flood plain.

Saturday, April 3

Hiking on the mesa & why mockingbirds mock

I hiked for about 35 minutes on top of West Mesa --- such a nice place. Some wind but not bad. Yellow grass bending in the wind. Bird songs carried by the wind.

There, I can see for 75 or so miles to the north to the Sangre de Cristo mountains near Sante Fe,
to the east I see the nearby Sandia Mountains, and to the west, the extinct volcanoes. But mostly, I bask in a vast open area of sky, clouds and grassland. I heard meadowlarks and mockingbirds singing.

Later, at home, I wondered why mocking birds imitate calls of other birds. What possible benefit could they get from such behavior? Birds usually sing to attract a mate or defend territory. How could singing another species' song help?

So, I looked up mockingbirds and learned the males are indeed trying to attract female mockingbirds by increasing the size of their repertoire.

Apparently, the mockingbird doesn't fool other birds all of the time. Maybe a mockingbird can effectively copy a repetitive song like the Carolina wren's or a red-winged blackbird but not long complicated songs like the song sparrow's. The mockingbird female, however, knows a male mockingbird when she hears one, no matter what song he imitates.

A male might have 50 to 200 songs in his repertoire and continues learning new ones all his life. Females sing, too, but not as much as males. Mockingbirds sing the loudest in early morning twilight, but also sing at night, especially if the moon is full, they are male and single.

Actually, we don't fully understand why a mockingbird mimics other birds' songs. The increased-repertoire theory seems reasonable and is probably true. Bird experts have hypothesized other reasons too:
  • defending an individual mockingbird's territory against others within his species
  • promoting recognition of an individual mockingbird
  • deceiving competitors by making it appear that many of the competitor's predators live in the area.
The birds also mimic other animals and mechanical sounds (such as car alarms).

Tuesday, March 9

A walk along the Rio Grande River

I had a nice long river walk today. About an hour and 10 minutes worth and my legs feel fine, at least now. I went north this time and ended up beside the river for most of the northerly jaunt. But then veered west along a maintenance road that apparently services those angle metal beam fences placed perpendicular to the river to control flooding, I guess. These fences were in the flood plain but high and dry.

When I realized how long I'd walked, I turned around to head back to the car, but thought I'd like to walk south along the river if I could, not in the bosque where I was. I found an easterly river-bound path and followed it to a wide sandy area where the river once flowed but now is considerably west of the present river bed.

I tried to fight my way through willows to the river but it soon looked like more trouble than it was worth so I stumbled my way back to the sandy area and went south again. Soon I came to game trail heading east again through the thicket to the river. I went along it and, sure enough, reached the wide flowing river.

Waterfowl galore --- a whole flock of Canadian geese floating on the river. Actually they were paddling upstream but staying stationary with respect to me as the current carried them downstream at about the same speed as their upstream paddling. Two geese were standing on a mudflat and looked so huge I first thought they were swans, silhouetted against the sun.

Many different types of ducks. Mallard ducks, which I recognized, and others. Bird cries, squawks, honks. I could have walked right up to an island where ducks waddled but didn't want to scare them. I headed back inland, walked a bit more south and followed another path back to the river, which I followed to the bridge and then to the car.

It was beautiful. A river full of birds, cottonwood-tree bare branches against the blue sky, white clouds, and the white Sandias.