Saturday, September 7, 2013

Yellow Bellied Sapsucker Camouflage

 Yellow Bellied Sapsuckers are a kind of woodpecker found in this area.  The young juveniles are out of their nests and getting ready to migrate to southern states soon for the winter. 

I took these pictures yesterday afternoon on a Burr Oak tree. 

The picture to the left shows how well they blend in with the bark of the tree.  They sit very still and are hard to see unless the light is behind them. 
Adult Sapsuckers peck rows of holes in tree bark and eat the sap and bugs that get stuck in it.  But this juvenile was not doing any of that behavior, and it would not work on an oak tree if it tried.

But its camouflage is working very well.

Monday, September 2, 2013

Black Swallowtail Butterfly Emerges

 This is the Black Swallowtail Butterfly that the caterpillar of my post several days ago turned into. 

They are beautiful, big, colorful butterflies with a very black background color.

In my previous post the caterpillar was preparing to change into the chrysalis portion of its life cycle. It sat quietly for a day before shedding its skin one last time to become the chrysalis.
 Here is the chrysalis immediately after it has emerged from the caterpillar skin. It moved very little at this point and had this very green and yellow color. 

By the next day the green color was starting to fade and become more brown.
 I had five caterpillars that each changed into a chrysallis.  While the caterpillars looked identical, each chrysalis was a different pattern and color.  Three became very tree bark in their color, and were very camouflaged. Two stayed somewhat green and yellow. 

Black Swallowtails overwinter in this chrysalis form here in Minnesota, and I thought that might be what these tree bark looking chrysalises might do.  But after 12 days for each, four of the chrysalises have now had the adult butterfly emerge.  Perhaps the remaining 16 day old chrysalis will wait until spring.
Immediately before the emergence, each chrysalis became quite transparent, and the butterfly's wing and body colors could be easily seen. 

It seems these buterflies like to wait until full dark to emerge, as I waited up very late several nights and missed all but this one as it was emerging at 5 AM last Thursday.

There is no movement, and suddenly the chrysalis cracks open and the butterfly quickly crawls up the plant stem to find a spot where its wings can hang and expand.
 Only seconds after emergence, the new butterfly's very large abdoman can be seen here pumping fluids into the tiny unfolding wings.

Notice the very prominent greenish yellow veins in the wings, through which the fluid can be seen flowing as the wings rapidly expand.

 Within an hour the wings are fully expanded, but pretty limp so the butterfly needs to continue to hang quietly to let the wings harden. 

The butterfly occaisionly tries to open the wings, but they are not strong enough yet and flop to the side mostly.
 Here the wings are stiff enough to be opened, but still weak.  The greenish yellow veins are only two hours out, and still pliable.

The new butterfly moves its proboscus mouth open and closed repeatedly during this time to get it ready for its first meal of flower nectar.
 Here after 4 hours the wing veins are completely black and hardened for flight.

I released each butterfly on flowers hoping to photograph it outdoors.  But each butterfly immediately flew high up into the sky and into the top leaves of trees near by.

I hope this butterfly's large abdoman means it is a female with lots of eggs to be laid yet this summer so more Black Swallowtails will be seen next summer.
 As the butterflies were emerging at night, it was often the colors of sunrise when I was first able to photgraph them.  They would open their wings and show their colors if frightened.  I believe the "eye" like colors at the bottom of the wings are meant to scare off possible predators. Seen up close these "eyes" are quite bold, as can be seen below.

Sunday, September 1, 2013

Confusing Fall Migrating Warblers

 Last night's north winds brought cooler weather and lots of migrating birds into the area.  This Chestnut Sided Warbler is headed south for the winter, where it wants to blend in and survive predators. So the bright colors of Spring are molted to these more muted colors. No chestnut sides now. We caught and banded this warbler this morning brfore releasing it.
 This Mourning warbler was another one that flew into the mist nets this morning. 

It is one of the confusing fall warblers whose muted migration colors make it look very similar to other warblers.

One of the only ways to separate this warbler from the Common Yellowthroat warbler in the fall is to compare the length of the feathers under the tail pictured below.
 The bird on the right is the Mourning warbler.  Its under tail yellow feathers (coverts) are quite a bit longer than the same feathers on the Common Yellowthroat on the left.  The length of these feathers helped us identify these birds. 

Banding birds requires a lot of very specific observations and measurements to be turned in with the banding data.

The rumpled feathers on this Red Start warbler's head are left over from the bander separating the feathers to see if the skull bone tissue was fully formed.  It wasn't, a confirmation that this bird was a nestling this summer.

The orange feathers under the wing indicate this is a male, and will have red and black feathers in the spring when he returns.

Warblers are beautiful birds, even without all the details.