Tuesday, November 13, 2012

Bald Eagles Aplenty

Each November, the approaching winter brings about a concentration of Bald Eagles to locations where there is easy fishing. This only lasts three or four weeks for the adults.

I just returned from a three day trip to one such place with good results.  There were easily two hundred Bald Eagles with a mix of adult pairs and juveniles; all were waiting for the hydroelectric units to roar into action and dispense a buffet of stunned fish.  I soon saw that  some were skilled at snatching fish from the river, and some were, well,  not so good. The latter were typically inexperienced juveniles who are now without parents to catch fish for them.  This was a great opportunity to build my skill at tracking the fast moving birds and timing the shutter release for the critical events.  It was basically batting practice for birds-in-flight (BIF photography).  Great fun too.

My first object was to capture the aerobatics of the eagles as they circle overhead.  Not so easy with the narrow field of view of a telephoto lens.  You have to get the lens onto a fast moving bird, lock focus and keep on the bird as it sweeps across the river.

When an eagle spots a fish, it can easily turn quickly and dive down for a closer look.  I love the way that they can throw their legs out and drop the tail to swing around.  Leaves me envious.

Once down to the right elevation, the eagle usually makes a shallow glide to the target and, at the last moment, throw its talons out to snatch the prey.

Those talons present quite a formidable array, and only a few points need to make contact.

I believe this catch was a small Walleye Pike.

The power turbines are usually active at sunrise when electrical usage jumps up.  Having roosted overnight, the birds are hungry.  The early morning activity is pretty intense and the low light a challenge for photography.  But the birds can be beautiful in the soft, warm light.

I think the graceful curves of the wing feathers are especially interesting as they  flex in the moving air.  This is only visible because the camera can freeze the motion.

Now, there is a lesson about survival in the natural world that we should recognize.  There is little room for social graces and politeness when an animal must eat or die. Robbery is a common event among eagles. Here are two juveniles in such a duel.  The trailing bird can fly faster and maneuver more nimbly than the bird with the fish. It easily overtakes the other bird.

Look closely at the first bird's tail. It is a fish's tail, not his.  He's already begun to voice his anger.  It is simply easier to steal a fish than to catch it.  So, juveniles especially attempt this on other juveniles or adults alike.  I saw a particularly good example among two adult eagles.  The attacker is on the left.

As is often the case, the attacker did not get the fish.  You can see it dropping to the river.  The victim voices his anger at the attacker on the left.

You may rightly wonder who got the fish?  Neither.  It sank.  The victim immediately flew off, and the attacker searched without luck.

So, how can an eagle ever get to eat its catch with so many robbers about?  I saw one example that may shed a light on the question.  This bird has a relatively small catfish.  He flew into a densely branched Beech Tree so that any attacker would be limited in approaching.

You can also see that the eagle was pretty vigilant, keeping an eye to the sky.

There is one other aspect of this to address.  With two hundred or more eagles eating several fish a day, who cleans up after all of this?  Eagles don't exactly clean the plate.  Nature has a pretty efficient system for this.  Here it is.

This is a Black Vulture.  A cousin of the Turkey Vulture, it has a taste for fish rather than rodents. So this relatively unusual bird finds it way into a small area around the hydro plant; it is found nowhere else in the area. There are  a comparable number of BVs waiting to dispose of the leftovers from the large number of eagles.  Now,  I know what you are thinking, but what would your life be like if no one took your garbage away?  They are actually very graceful flyers too.  I just would not recommend standing under one of their roost trees.

I'll post my most exciting images later after I have had time to edit all of my photos.