20 July 2010

Photo Essay of a Cordilleran Flycatcher Nest

The past few weeks have been nesting time for many birds in our area.  One of MNHC's long-time volunteers and supporters, Kim Birck, has been watching one type of bird--and one nest--in particular, a pair of Cordilleran Flycatchers (Empidonax occidentalis) who chose her power box upon which to build their nest.

















Cordilleran Flycatchers are small birds with greenish-brown backs, yellowish underparts, and a slight crest on the head.  Distinctive features include a pale yellowish eye ring and wing bars.   The Cordilleran flycatcher is virtually indistinguishable from the Pacific-slope flycatcher--in fact, they were once thought to be the same species and were called Western flycatchers.  The only difference between the two species is the male's voice--and their range.  Cordilleran flycatchers breed in a long north-south swath of the western U.S., from southern B.C. and Alberta into Idaho, western Montana, Wyoming, Utah, Colorado, Arizona, New Mexico, and into the northern edge of Mexico.  

Flycatchers are so named for their feeding habits; they swoop down from their perches and catch flying insects in mid-air, though they will also hunt for insects hiding in the branches of trees and shrubs.  Some flycatcher species will also eat berries or other types of food. 

Cordilleran flycatchers are commonly found in dry, shaded forests at mid-high elevations. 

While they usually nest in trees, occasionally they'll find other convenient locations--in Kim's case, the top of her power box at her home.  She was very happy to share with us both her pictures and her observations.  Enjoy!

24 May:  I just saw a little Cordilleran flycatcher yesterday, back from wherever he/she winters.  (Mexico, it seems.)  Maybe my power box will have another nest, for the 5th year running! 

9 June:  He's back again!  I was repotting herbs nearby while my little flycatcher friend was checking out the nesting site on top of the power box. 

10 June:  Well, today, THIS showed up!

















11 June:  I hope I haven't scared him/her off . . . perhaps not.  The nest looks bigger today:




















12 June:  She's at it again today.  Watched her mashing down the nesting materials (mostly lichens and moss?) with her body.  Here's a fuzzy image of her on the nest:




















Fuzzy because I used digital zoom, not wanting to get close enough for optical zoom.  Once she has eggs, she'll be harder to dislodge.  But for now, I want to keep her as my neighbor.  Seems like good luck to have a bird nesting on your house.

14 June:  Set up a bicycle mirror on a broomstick that allows me to see into the nest.  No eggs yet!


She isn't around much lately.  I suspect she is gathering her strength after nest-making before egg-laying, as my book (Peterson Western Birds' Nests) says the female does the nest building and the incubating.  One egg per day for a clutch of about 4.  When the clutch is complete, she incubates for about 14-15 days, then both parents feed the nestlings for about 2 1/2 weeks before they get too big for the nest and fledge.  

15 June:  I hear them calling, so I know they're around . . . but still no eggs.

17 June:  This morning, before we left on a 2-week trip, I checked the nest and there was one egg!  During our absence, she should complete the clutch and do most of the incubating . . . and be fully committed to the nest by the time we get home.  BTW, my husband recently admitted that when he was blowing dust and pine pollen off the porches and windowsills with a leaf blower he accidentally blew the flycatcher's nest off the power box.  He carefully replaced it and it seems to have worked.  The egg this morning is the proof!

2 July:  When we returned home, I found mama flycatcher sitting on these:


Note the brown splotches wreathed around the large end of the egg.  This is typical for Cordilleran flycatchers.

4 July:  Mama bird was acting restless, spending more time looking into the nest before settling back onto the eggs.  Since the bird book says they incubate for 14-15 days, I knew hatching was imminent.  

5 July:  This morning when I looked into the nest, there was only one egg left, plus three naked lumps of baby bird flesh:
















Mama continued to incubate the nest,  when I thought she should be out catching bugs for her babies . . .

6 July:  We were cleaning windows this weekend and my husband went up on the roof above the breakfast nook--and the flycatcher's nest on the nook wall--to wash the upstairs windows.  I was tending plants nearby when I heard a flycatcher "shreek!" and saw it streak away from the house.  I looked up to see size 11 white tennis shoes hanging over the roof edge right next to the nest as he stretched to reach windows on the adjacent wall!  No wonder she fled!  I hoped that our maneuverings near her nest hadn't spooked her for good.

But she came back has been diligently "sitting on" the babies, all four of which had hatched by last night.  And at least one was alive last night, raising its little head--and gaping big mouth--when the mirror loomed overhead as I checked it out.

I have yet to witness food being brought to the nest, though.  Not to say it hasn't happened, I just haven't seen it.  We are trying to keep a low profile and avoid disturbing her, though her instincts would probably not let her abandon the babies now.  The windows closest to her nest are going unwashed, and I only photograph the nest when she has flown away.

7 July:  This morning:


Baby flycatchers sleeping while Mama is away.  And now I'm seeing TWO flycatchers.  And finally, late this morning, witnessed an insect being fed to somebody in the nest!  

4 pm:  Still spending a lot of time on the nest, even though the young are all hatched.


Both flycatchers--hard to catch them together as they are finally actively bringing insects to the nest this afternoon!


8 July:  I caught the nest unattended briefly this afternoon and snatched this image:


They are starting to look just a bit like baby birds.  Less like raw meat anyway.

11 July:  I frequently catch an adult feeding the young in my mirror, hanging from the eaves, but they won't come to the nest when I am outside with my camera.  Taken on Sunday, in the hanging mirror.  I can watch them from inside the kitchen without disturbing the birds. 


16 July:  I took this photo from a 6-foot ladder about 6 feet away from the nest while the parents were away:


Their mouths are open because they're hot (and hungry).  They are beginning to overfill their nest.  And now I can see that all 4 have survived.  So far.  Ravens prowl the neighborhood looking for such tasty morsels!

17 July:  The first three babies hatched on July 5, and the Birder's Handbook (Ehrlich, Dobkin & Wheye) says they are in the nest 14-18 days before fledging.  So they will have to grow up a lot in the next few days as today is Day 13!

19 July:  The afternoons have been quite hot lately, and the little ones look like this a lot of the time:


They wake up pretty quick when Mom or Dad arrives with a tasty insect!


Sometimes the parent bird gives a heads-up "peek!" as it arrives, so the little ones assume the position and no time is wasted.

20 July:  We are off for a week-long hiking trip.  The baby birds are about to fledge, and will probably be out of the nest by the end of the week!  A fifth season of nest-watching is ended.