Back in the Field!

Truckee River

Across the nation, bird biologists are gearing up for the upcoming field season, and GBBO is no exception.  Here’s a run-down of the field work that we’re starting up over the next couple of months.

We’ve mentioned before our efforts to monitor the populations of fish-eating waterbirds on Walker Lake and other terminal lakes in western Nevada, and this work is continuing. The ongoing drop in the water level in Walker Lake has led to increasing concentrations of dissolved solids, decimating the lake’s fish populations and the birds that depend on them. If ongoing efforts to secure more water for Walker Lake are successful, we hope we’ll be able to document waterbird recovery in the future.

Pine Nut Range

Also on the docket is our statewide Golden Eagle inventory project, in collaboration with the Nevada Department of Wildlife, where we’re working together to better understand how eagles are distributed statewide, so we can provide the Bureau of Land Management and other agencies with the information they need to protect Golden Eagles in the face of energy development pressure and other possible conservation challenges. 

Starting up is a new Elf Owl study in the Mojave and Sonoran Desert regions of California and Arizona. This will be our second Elf Owl project for the Lower Colorado River Multi-Species Conservation Program (LCR-MSCP).  The Elf Owl is a conservation priority species for this program, and our project is designed to better understand the habitat needs and preferences of this tiny owl, so that restoration activities along the LCR can be designed to provide maximum benefit. 

Elf Owl, copyright & courtesy of John Stanek

We are continuing to use the expertise and skills developed in designing and implementing bird surveys and monitoring projects to benefit management programs for stray dogs and cats in the US, and around the world.  Free-roaming cats and dogs can have negative impacts on wildlife and public health, and they also suffer from frequent abuse and neglect. Previous efforts to manage stray animal populations have often been ineffective because of insufficient monitoring, lack of analytical rigor, and a poor understanding of animal population dynamics. By providing consultation services to organizations that are seeking to better manage stray animal populations, GBBO is helping to rectify these oversights and ensure that stray animal management programs are effective.

The Lower Colorado River program continues this year – and, in fact, trail clearing starts up next week! Since 2008, we've been conducting area searches within riparian corridors in the river's historic flood plain as part of the LCR-MSCP.  We're surveying sites where riparian habitat has been restored, as well as those on federal, tribal, state, and private lands to obtain population size estimates, trends, and distributions for six LCR-MSCP species of concern (Gila Woodpecker, Summer Tanager, Arizona Bell’s Vireo, Sonoran Yellow Warbler, Gilded Flicker, and Vermilion Flycatcher) as well as many other riparian birds. Along with this population monitoring, we're also developing detailed habitat assessments for the first four of the above species.  More details can be found in our annual reports at http://www.lcrmscp.gov/steer_committee/technical_reports.html. 

In 2013, we began a new component of the project: monitoring potential impacts of saltcedar beetles on riparian birds of the LCR.  Here, in the center of the invasion by the saltcedar beetle, we are able to study the effects of defoliation as the impact unfolds. Impacts of defoliation may be sudden or they may occur over an extended period of time.  For example, sudden effects might result from nests being exposed to the sun (and thereby to higher temperatures), or by depressing insect populations through  sun exposure.  Alternatively, impacts might occur over time as suitable habitat becomes less and less available because of the lack of canopy cover and lack of recruitment of other suitable vegetation.  This season will be the second of the three-year project.

Last but not least – and near and dear to my (Jen's) heart! – is the Nevada Bird Count.  The NBC is a statewide bird monitoring program (with a few surveys dispersing out into adjacent states), that focuses on point count transects supplemented by area searches – and a whole lot of habitat assessments!  I just checked our database, and we have 892 transects set up so far; in 2014, we’ll be surveying a subset of these, along with a number of new locations.  The NBC acts as a sort of umbrella, encompassing a lot of different projects.  This year, we’ll be continuing our surveys at Warm Springs Natural Area, as well as those along the Truckee and Walker Rivers.  The Pine Nut Range is another big project area, where we’ll be investigating pinyon-juniper treatment areas as well as fire impacts from last year’s blaze.  We’re also going to be looking at bird communities in sagebrush and blackbrush habitats in the Great Basin and Mojave Desert, particularly in relation to linear disturbance factors like roads and powerlines.   Finally, we’ll be monitoring restoration areas at Pahranagat and Desert National Wildlife Refuges.   It’s going to be fun!  There are several more NBC-related projects in the hopper, too, so stay tuned!

Happy birding,

Jen, John, and Amy

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

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

Pinyon Jay Project Update

GBBO has been continuing its work to better understand the causes behind the rapid, ongoing decline in Pinyon Jays.  This decline of 4-5% per year has been occurring over the last 30 years, and has been well-documented by BBS data. However, its causes have not yet been adequately explained, in part because Pinyon Jays have been a poorly studied species in much of their range and present many challenges for field biologists. Nevertheless, we have been successful in efforts to deploy radio tags on Pinyon Jays, and have over the past year conducted a detailed nest study and habitat use assessment in the Desatoya Mountains of western-central Nevada. 

Although data from the last year are still being analyzed, all of our findings to date are consistent with a picture of Pinyon Jays as a species that prefers transitional ecotones between pinyon-juniper woodlands and sagebrush.  Because many of these mixed-age, mixed-structure transitional areas have been supplanted over the last century by larger and denser pinyon-juniper woodland patches, we are hypothesizing that the Pinyon Jay's preferred landscape has been reduced in extent. This suggests a possible mechanism that may have contributed to the Pinyon Jay's documented declines, and one that has ramifications for current pinyon-juniper woodland management practices. GBBO will continue its efforts on behalf of Pinyon Jays, and we will be presenting our findings and recommendations in publications in the near future.

- John

Waterbird Surveys

Dennis and Bob surveying on Walker Lake

GBBO has been monitoring populations of fish-eating birds over the last year on several western Nevada lakes, including Walker Lake and Pyramid Lake. Our monitoring efforts occur year-round, although they are more intensive and frequent during the spring and fall migration periods. Our goals are to better understand how waterbird populations at Walker Lake have, and are, changing as the lake shrinks, as dissolved solids increase, and as fish populations decline. We are also interested in determining the extent to which other nearby lakes "take up the slack" and provide habitat for birds that formerly used Walker Lake during migration. 

At present, Walker Lake exhibits substantially reduced numbers of several fish-eating waterbird species, and very large populations of phalaropes and Eared Grebes, which feed on the aquatic invertebrates that thrive in saline lakes. In these respects, it is becoming similar to Mono Lake, but we consider the situation to be reversible if water deliveries to the lake increase again.  Our monitoring program will continue, and as efforts to increase inflows to Walker Lake bear fruit, we can document recovery of its fish-eating waterbirds.

- John

Happy Thanksgiving!

In honor of Thanksgiving, I’d like to share a few fun photos of Wild Turkeys, brought to you by our friends at The Yurt, John Woodyard and Melissa Renfro!

One of their recent arrivals is a leucistic Turkey, below:  

 

Last, but not least, here's a cool video of a couple of toms duking it out in April:

Have a Happy Thanksgiving, everybody!

--Jen

All pictures/videos on this post copyright and courtesy of John Woodyard.  Thanks!

Gray Vireos: A Coda

Gray Vireo, photo copyright & courtesy of Deb Vogt

Thanks, everyone, for the Gray Vireo emails and all the location info!  (Just so you know – I really use that location information, entering them into one of my databases – next year’s map will be including all of these new sites!) 

I wanted to share a few photos Deb Vogt sent me – in June, she found a pair of Gray Vireos and their nest down in southern Nevada.  She thought they were feeding a fledgling deep in the tree – one parent “cussed her out”, while the other sang.  I hadn’t seen a Gray Vireo nest before, so I was happy to finally get to see a picture, at least!  Thanks, Deb!

Happy birding,

Jen

Gray Vireo nest, copyright & courtesy of Deb Vogt