Naturespeak A naturalist's view of the world

July 19, 2007

Over Easy

Filed under: Uncategorized — wykes @ 9:46 pm

  There is no such thing as a plain “sparrow.”  In nature, everything is specific and particular, so it should be no surprise that there are 15 different kinds of sparrows in the lower Great Lakes area. Oddly enough, this number doesn’t include the English sparrow – you know those birds that nest in the “e” at the Meijer store.  English sparrows aren’t really sparrows at all, but are weaver finches of the old world tradition.

  The Song Sparrow is a specific kind of true sparrow with a particularly nice way of phrasing things.  These small birds are typical members of a clan where the male and female look alike and both are variations of a brown and white bird. As it happens, there are a lot of potential fashion statements to make using a “brown & white” palette. The songster has some wonderful chestnut brown tinges and a heavily streaked breast with a central dark spot (take a look here). Unfortunately, brown birds don’t usually get noticed by our species and they must yield the stage to the flashy feathered flock.

  Like their kin, Song Sparrows would go on in complete anonymity were it not for their loud bubbly song. Various writers have put the verse into English as “Madge Madge put on your teakettle” but this hardly does it justice. Take a listen here at a song recording and judge for yourself.  The bird outside your backdoor will not sound exactly like this, however, because their song patterns vary widely in different parts of the country. They have dialects nearly as dramatic as the difference between a Texas twang and a nasal Canadian “put on yer teakettle, eh?”

  Song sparrow babies learn their phrasing and song bits from listening to their parents as well as eavesdropping on their neighbor sparrows. Each bird comes up with a similar, but different way of saying things than their parents. Since our children do the same, whether they will admit it or not, this should be a familiar concept (as in “let Madge get yur teakettle, dude, I’m chilling here.”).

  I am getting ahead of myself at this point, though.  You don’t have baby sparrows unless the eggs hatch properly and they won’t hatch unless mom sparrow does her job right.  Tucked neatly away in a flower bed a female Song Sparrow is in the process of doing just that right now.  She wove a neat fist-sized nest out of dead grass and elected to place it about a foot off the ground. The inside is lined with a bed of fine grasses. In this species the male does not take part in any nest building or incubating, but will re-enter the picture once the young are hatched.

  Over the course of the week, three beautiful eggs were laid in the nest and she has begun incubating them.  You’ll see the eggs in a moment, but I’d like you to see this photo of her on the nest first.  She’s tucked down and deep with her tail and head pointing up. It was difficult to get this shot because these sparrows have a habit of jumping out of the nest whenever potential danger approaches.  Like a little field mouse, she’d hop over the edge and jump down into the protection of the flowerbed.  As long as I – the dangerous one – was in the vicinity, she scurried about silently in the undergrowth. Although leaving here brood exposed like this may not strike you as motherly behavior, my close observation of the eggs proved that she was indeed doing her maternal best. 

  Each time she scurried, I was able to take a quick, but close, look at her eggs and snap a picture of them.  I did this three times over the course of the day before successfully getting her portrait while sitting on those eggs.

    The first shot (see here) reveals the three eggs I was speaking about.  They are light bluish green and only about a half inch long.  Each is speckled with a distinctive spattering of chocolate spots which grades from heavy on one end to light on the other. Note the “top” egg, which presents a fairly speckle free side with an elongated spot at top center.

  Six hours later, (see here) the skittish songster again hopped away and I decided to shoot the eggs again.  This time, I noticed the egg positions were all changed. The “top” egg had been rolled over easy about 90 degrees (look at the elongated spot), the “left” egg rolled to the right the same amount and the “right” egg completely flipped end for end.  A few hours later (see here), the “top” egg had become the “right” egg and the “right” egg the “top” egg, and the “bottom egg rotated to the left by 90 degrees.

  As part of the incubation process, our female was rotating her eggs as all good feathered moms should. This is part of the incubation process often goes un-noticed in wild birds. If you’ve ever hatched chicken eggs, the rolling thing is old hat. It is advised to rotate the eggs at least three times a day and to vary the direction of the roll. Putting a large penciled “X” on the egg allows the caretaker to keep track of the sequence.

  A female Song Sparrow instinctively keeps track of her rotation duty as faithfully as a fully powered “Turn-X Incubator.”  The question is begged as to why egg moving is necessary in the first place. It has much more merit than just evenly warming the eggs.  Rotation prevents the inner membranes from sticking to each other and stimulates the growth of those membranes, increases embryo heart rate and helps it to absorb nutrients, and facilitates the developing chick to settle into hatching position.  As non egg laying animals, we don’t think about such things. It is nice to appreciate such a small thing in a small bird on a small nest.

  It will take two weeks until the little sparrows are ready to hatch.  Mom will stick to her post with half hour snack breaks over the day and constant rotation of the eggs. I’ll keep you posted when we get a chorus line of Song Sparrows hatching out singing “Keep your Sunnyside Up.”

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