Thursday, December 28, 2017

December 27, 2017: Three Great Blue Heron nests

Instead of viewing the heron colony from the same spot, I found another spot under the tree and saw the three nests.

Three Great Blue Heron nests: one in the upper left, one in the middle right and one in the middle bottom

Heron 3, apparently incubating one or more eggs

Heron 2, standing and waiting

Heron 1, standing above her nest

December 27, 2017: International Space Station Pass

Finally I got it right. This morning there was a bright pass of the International Space Station - magnitude -3.1 at 6am (an hour before sunrise). There was a convenient power outage that reduced light pollution.  Now lens condensation from ground fog,  no lens cap obscuring the sky and the ISS was where it was supposed to be.

International Space Station track (30 second exposure)

Passage of the International Space Station through the star field.   11mm lens, f/4.0, ISO 200. 2 min exposure
February 25, 2018 05:46.   Superimposition of 3 30 sec exposure, ISO 100 f/2.8

International Space Station pass;  05:46 Feb 25, 2018, Superimposition of 3 30 sec exposures

Tuesday, December 26, 2017

December 24, 2017 . Great Blue Heron - nest building 102 and love making 101

I don't get it -   how they weave twigs together to make a cohesive nest with no holes in the bottom for eggs to fall through.  How is this "instinct" programmed?

The colony of Great Blue Herons in the top of this pine tree

Incoming twig

A large incoming twig

Passing the twig to the female

The next door neighbor watching

Another incoming twig

From time to time there is a breat in nest building - more "kissing" -  bill touching and holding

Perhaps mounting the female for copulation

Tuesday, December 19, 2017

December 19, 2017: Great Blue Heron Bill slapping

I've been watching the behavior of a small colony of Great Blue Herons.  Three - maybe four nests in the stop of a pine tree.

I've found a very useful reference:  Pair-formation displays in Great Blue Herons.  

I've noticed that pairs of Great Blue Herons make a slapping sound that seems associated with "kissing" - grabbing each other's bill and then drawing back which creates the slapping sound.  Apparently this display is called bill slapping (or something similar).  here are some examples.

One grabs the bill of the other

There is an alternating thrust of one and then the other

Here the left heron retreats

and the right heron starts a thrust

Right heron thrusting

Bill biting

Wing flapping to stabilize the right heron's position

Finally he is tired of this display and leaves


Monday, December 18, 2017

December 18, 2017: Great Blue Heron, nest building 101

Watching Great blue heron nest building. I'm looking for cues to identify when the male is near with a twig.  So far, the female seems to stretch her neck as a prelude for the male's appearance, but not every time.  I’ve found a very useful paper describing the behavior of Great Blue Herons

At this point, the female seems to be in charge of construction, with the male flying off to a convenient tree or vine, harvesting a small twig and returning to the nest.  He passes the twig to the female who then weaves it into the nest.  They have a short chat and he departs to repeat this action.  The images below illustrate various elements of this process.

My "Heron" tree.  There are three nests in this tree - one in the lower right (you can se the occupant), one in the middle (occupant mostly hidden) and a third nest above and behind this nest (the occupant is standing on top of a limb (perhaps waiting for a twig).

A discussion between male and female

Male bringing a twig for the nest

Male passing the twig to the female

Female grasps the twig in her bill

A neighbor

I'm not certain what this bill touching is all about - kissing?

Departing to search for another twig

Returning with a small twig

Returning with a large twig

Preparing to land and pass the twig

Bringing another twig

I've yet to capture how the male harvests twigs - but here is another episode of twig fetching

Bringing another twig

And another -  after all, you build a nest 1 twig at a time

I'm not sure what this is all about - perhaps two males in search of a female?

There is an interesting "dual of bills" between the male and female

Here one grabs the beak of the other

Flying away