Thursday, January 23, 2014

Lucy's Warbler Nest Sites

Lucy’s Warblers are a species of conservation concern here in Nevada.  A small, cavity-nesting warbler, in Nevada they’re found primarily in riparian areas and mesquite woodlands. They typically nest between 0.6 and 6m above ground, in a wide variety of locations, from crevices formed by loose bark, to natural cavities, to old woodpecker cavities – even (rarely) crevices or burrows in rocks or banks [1].

I’ve been fortunate over the past two years to find and photograph several Lucy’s Warblers nest locations at Warm Springs Natural Area.  Unfortunately, they’ve all been too high and/or too hidden to actually get photos of the nest itself – so no cute pictures of nestlings, I’m afraid!  However, I thought these might be useful to help develop your own search image for Lucy’s nests.  Playing about online, I also found a short video of a Lucy’s Warbler building a nest (aka entering a cavity with fluff), that I thought folks might enjoy. 

Okay, on to pictures!

This first one exemplifies the nests that were in the burned screwbean mesquites, with the Lucy’s Warblers building in “cavities” created by peeling bark.

The next 3 pictures show Lucy’s Warbler nest locations behind peeling bark in burned-over cottonwoods.  In the third set, this nest was located in the same tree as a Western Kingbird nest.  The Kingbirds lived up to their genus name, Tyrannus, and were very territorial.  On one occasion, I watched the Kingbirds prevent the Lucy’s Warbler pair from bringing food to their nestlings for over 3 minutes (and I’d arrived in the midst of their dispute and been watching for some time before I thought to look at my watch!).  



This nest location in a burned cottonwood was featured in a previous post, and the nesting attempt was evidently abandoned.  Two other species  began nesting in this snag, as well: Brown-crested Flycatcher, and Western Kingbird.  These also abandoned their attempts.  This could be chance (I did see several other nesting attempts by Lucy’s Warblers and Western Kingbirds that didn’t go anywhere), or perhaps the lack of shading from any other vegetation led to it being too hot, or [insert your explanation here!].  On the other hand, it was the most heavily-used perch tree on my plot, by a wide variety of species!

Below is a Lucy’s Warbler nesting site behind some peeling bark of a burned-over cottonwood that is resprouting.  This tree served as a nest site for 2 successive years; in the second year, the new growth had become tall enough to hide the site from view.

Last, but not least, is a Lucy’s Warbler nest location within a natural cavity within an ash.  I had walked by this location numerous times during my surveys, without realizing the nest was there – on this survey, the pair was bringing food, and the nestlings were creating a racket!  (You can see feces on the nest’s rim, from either older nestlings or the female.)

 
Well, that's the end of my photos - happy nest finding!

- Jen


 [1] Johnson, R. Roy, Helen K. Yard and Bryan T. Brown. 1997. Lucy's Warbler (Oreothlypis luciae), The Birds of North America Online (A. Poole, Ed.). Ithaca: Cornell Lab of Ornithology; Retrieved from the Birds of North America Online: http://bna.birds.cornell.edu/bna/species/318

Thursday, January 9, 2014

Vermilion Flycatchers: nests, nests, nests

I was tagging photos last month, and realized I had a fair number of Vermilion Flycatcher nests, so I thought I’d share them: (1) because they’re interesting, and (2) because I figured they may help folks develop their own search image!  Sadly, I had some great ones a few years back, but the camera they were on fell into the Walker River before I’d had a chance to download them.  (And yes, I now clip my phone to its case – and the case to me – just to prevent this sort of thing from happening again!  Lesson learned.)

All of these photos were taken by me at Warm Springs Natural Area, except for one by Amy Leist down along the Lower Colorado River (thanks Amy!).  Of the pictures at Warm Springs, only one nest (2 pictures) is from prior to the 2010 fire (again, see The Walker River Incident), and most are from 2012-2013.  Interestingly, the fire didn’t seem to impact the Vermilion nesting as much as expected (at least on a short-term basis): as you can see, the majority of these nest photos are within burned and leafless screwbean mesquites and cottonwoods.  This may be because, even prior to the fire, they typically began nesting early while the screwbeans lacked leaves, anyway.  Depending on the photo, it may not be obvious, but the nests were shaded for significant portions of the day.  The exception was a nest in 2012, which was fairly high up in a burned tree, and did not have that shading – the female there ended up spending a lot of time acting as an parasol!

Based on their Birds of North America account [1], the most important nest trees include willows, cottonwoods, and mesquites.  As I mentioned, at Warm Springs, they appear most frequently in the cottonwood/screwbean mesquite habitats, but also use honey mesquite.  In the literature, honey mesquite appears more frequently than screwbeans, which is unsurprising given it has a much larger range.

Nests are typically located 2-6m, and up to 18m, off the ground, though this depends greatly on the kind of habitat they’re in – nests in cottonwood habitats are understandably much more apt to be higher than those in shorter mesquite stands.

This first photo was taken in 2009 – you’ll have to squint to find the nest, but you can see some fine nest material on the top of the branch – the nest itself has been constructed within a forked branch.  In the next photo, the black arrow points to the nest location relative to the screwbean plant itself.  This stand had large numbers of Vermilions in it, and was a fairly open screwbean mesquite stand with scattered honey mesquites and quailbush, and (often) a dense carpet of grass.



Here’s another photo of a nest within a screwbean mesquite.  As you can see, this mesquite hasn’t yet begun to leaf out significantly.  Unfortunately, I don’t have a photo of the nest location relative to the rest of the plant, but the nest was a little under 6 feet high, and probably just under half the height of the mesquite it was in.  Again, the nest is in the fork of a branch.


 



And another nest within a screwbean mesquite.  Again, the nest is constructed within a fork, and was approximately 6 feet high.








Moving on, here we have a nest in what I believe is a dead (burned) ash, and a landscape photo – you can see the dead branches from the “ash” in the center of the photo (background).  I evidently didn’t write down the height of this nest, but it was probably about 7 feet high (it was well over my head).  (**)  This was taken in 2013.


The next two photos were taken in 2012 and 2013, in another scorched ash – though in 2012, it still had some leaves.  As you can tell, they refurbished the same nest location!  A third photo, with the arrow, shows the nest location relative to the rest of the tree.

Vermilion Flycatcher nest, 2012

Vermilion Flycatcher nest, 2013



This pic, taken in 2012, may be in another burned screwbean (it’s a mesquite, at any rate), and is the one I mentioned earlier, that did not have shade … you can see the female standing on the nest’s edge in the photo.  This may be the same pair that is starred (**) above.  At any rate, this location is very close to that above.

Add caption


The next several photos are of nests within burned cottonwoods.  Some of these appear to be built within forks, others do not (or at least it is not obvious); all are on fairly flat sections of the branch, and are shaded by branches above and beside them.  







 


For a somewhat different look, here’s a photo Amy Leist took of a nest within a honey mesquite.






Anyway, that’s it for now!  Happy birding,

-- Jen



[1] Ellison, Kevin, Blair O. Wolf and Stephanie L. Jones. 2009. Vermilion Flycatcher (Pyrocephalus rubinus), The Birds of North America Online (A. Poole, Ed.). Ithaca: Cornell Lab of Ornithology; Retrieved from the Birds of North America Online: http://bna.birds.cornell.edu/bna/species/484