Looking back at 2021 continued: Owens Valley, Crescent Dunes, & Species Shifts

Owens Valley

Owens Valley Program

Kelly and Kayla run the Owens River program, and tag-teamed for this update! 

Willow Flycatcher nest with eggs and nestling

In spring 2021, GBBO began a three-year monitoring effort on the Owens River on Southwestern Willow Flycatchers (SWFL), Yellow-billed Cuckoo, Least Bell’s Vireos, and other riparian obligate species. Despite drought conditions, partners from Southern Sierra Research station detected over 100 SWFL territories using call playback. SWFL nests were also monitored for success and parasitism – 11 nests were found on 10 territories. While at least 6 of these were parasitized by Brown-headed Cowbirds, they produceed at least 13 fledglings. 

We were also joined by Murrelet Halterman, who conducted Yellow-billed Cuckoo surveys in the area.  Two cuckoos were detected (one was an incidental), though neither was thought to be territorial. No Bell’s Vireo were recorded during point counts, but we recorded 92 species along 10 point count transects. We look forward to surveying again this spring!

 

Kayla added

Nest with decoy egg

: These surveys are no joke and had us crawling through thick willow, wild rose, and stinging nettle all while hoping our rubber boots were tall enough to avoid wet feet. A fun encounter in one of the most densely forested parts of the riparian corridor was coming face to face with a Northern Saw-whet Owl (no photo, but an extremely cool sighting)! One of the interesting things we learned during Willow Flycatcher nest monitoring was to replace any Brown-headed Cowbird eggs found with decoy eggs. One of the reasons for using the decoy egg is to trick the SWFL parents into thinking that nothing has changed. If they notice fewer eggs in the nest, they may think the nest has been parasitized and abandon it. Another fun fact is if a cowbird lays an egg in a nest before a SWFL does, the SWFL may realize there is a foreign egg or object in the nest, prompting them to build another bottom layer to the nest covering the egg. This way, the cowbird egg won’t hatch. Overall, this was an exciting project and the awe-inspiring sunrises and sunsets of the eastern Sierras never got old. Though the days had their challenges, monitoring SWFL nests was extremely rewarding. Plus we had some adorable field dogs to keep us company and made the most of our time working in and around Bishop!

Monitoring Renewable Energy Facilities

 

GBBO continues to monitor the impacts of renewable energy facilities in on birds and bats by conducting ongoing standardized mortality surveys. In the Altamont Wind Energy Area of California, our teams are working on two sites to perform these surveys using highly trained dogs that locate mortalities by scent.  At the Crescent Dunes Solar Facility near Tonopah, human survey teams perform the searches. These efforts are critical in understanding and minimizing any negative effects of renewable energy production on birds and bats.  

 

- John

 

Species Range Shifts

 

I think everyone is going to talk about how hot and dry 2021 was. Every year there are seasonal differences, but the ones I saw this year were some of the starkest I’ve ever observed.  Rather than gloom and doom the place up, how about a less direct discussion of these changes!

In early 2021, many birders are aware, that the northernmost nesting attempt of LeConte’s Thrasher was documented, rather thoroughly by a few researchers. This nesting effort was ultimately unsuccessful, but suggests several important things.  The species has not necessarily been extensively studied, but those who have spent considerable time with them all note that they are not exceptional flyers, and do not disperse particularly far. This nesting site was some 200 miles north of the closest previously known nesting location. For a bird that is not described as a particularly strong flyer, that is a pretty impressive distance for not 1, but 2, birds of opposite sexes to travel and find each other. To me that really emphasizes the title of Jay Sheppard’s recent book, The Biology of a Desert Apparition: LeConte’s Thrasher. It seems likely that these guys are making smaller leaps, finding suitable habitat along the way, and making their way north. If only birding the salt desert were more exciting, we could get some more eyes out there…

A semi-related bird record is the appearance of Nevada’s second Barred Owl, while this is a review species in the state, and this record has not yet been reviewed by the committee, the photos leave little doubt as to this bird’s Identification. The Barred Owl is expanding south through the Sierra Nevada, and before that, the Cascades, and before that, west through the boreal shield. This pattern suggests we are likely to see more of them in Nevada. While the specific reasons for both of these phenomenon are the grounds of much speculation, it is nonetheless interesting to note we are seeing species coming south, and species coming north, of their expected ranges. Nevada is a large state that covers a lot of habitat, and as such, we are uniquely situated at the fringes of many species’ ranges.  In my mind, this makes Nevada an extremely interesting place to pay attention to the birds, as we see changes in climate such as those observed in the 2021 field season.

 

Ned

 

 

Looking Back at 2021: the Nevada Bird Count & IMBCR programs

Wow, how time is flying!  Our 2022 field work is now well underway.  We had a very successful 2021, and are bringing those experiences to the current year!  So we will be sharing a short series of blogposts to talk about what we were working on last year, and some of the highlights and maybe a few lessons learned.

I’ll start off talking about our Nevada Bird Count/IMBCR (Integrated Monitoring of Bird Conservation Regions) crew/projects.  It’s probably not a surprise to anyone, but man, 2021 was DRY. Scarily dry.  We started off helping out with surveys for the thrasher program in April - Dawn will be sharing some highlights from that later – and our southern Nevada point count surveys. I wrote up a blogpost on one of my thrasher surveys down there last year – you can find that here.  My overwhelming memory is of large numbers of desert shrubs, with few to no leaves – even the creosotes with brown dessicated leaves, and branches that had died back within the past year. Even the seemingly-ever-present Black-throated Sparrows appeared impacted – many did not appear to be breeding (unusually, I never saw any breeding evidence for them during my southern Nevada surveys). Even singing was affected – one creosote site where I’ve camped and surveyed most years since 2008, where there are always Black-throated Sparrows singing during the breeding season – I heard one singing a single short phrase at about 3 o’clock in the morning, and that was it.  It brought Rachel Carson’s Silent Spring to mind.  One of our sites in the southern Great Basin looms similarly large in my mind – very few birds singing, with many of the sagebrush only supporting a branch or two that contained leaves.

Our two primary Nevada Bird Count projects were located at Ash Meadows National Wildlife Refuge and along the Truckee River. Our Ash Meadows surveys were definitely a breath of fresh air amongst our other southern Nevada upland projects, and it was wonderful to be surveying near water!  My favorite survey was definitely our Crystal Reservoir transect that samples the wet ash meadows near the reservoir.  Summer Tanagers, a few Phainopepla and Vermilion Flycatchers, lots of Bewick’s Wrens … and wet feet!

Our Truckee River surveys continued work begun in the 1990s along the lower Truckee River, from Lockwood down to Nixon. As with our Ash Meadows surveys, we definitely appreciated surveying near water!  What stands out the most to me was the growth of the young cottonwoods (and a few willows) that had established in 2017-2018, and surveying points where once we’d had an unobstructed view for hundreds of meters, and now we looked out at a bank of young cottonwoods, their tops waving in the breeze.  On one of the long-term area search plots, where for years we had only had Yellow Warblers migrating through, now there were several territories, two with confirmed young.  It was incredibly heartening!

Upper McCarran #11, in 2019 ... you can see the young cottonwoods coming up!

Same place, 2021 ... you can just barely see the top of the hill & gallery cottonwoods!

Last but not least, we conducted 109 surveys of IMBCR plots for the BLM and Forest Service in Nevada and eastern California.  Our Forest Service surveys are only on the Humboldt-Toiyabe National Forest, and cover all three conservation regions, in the Carson Range/Sierras, Great Basin, and Mojave Desert.  Our BLM surveys were only within BCR 9 (the so-called Great Basin region). We definitely appreciated the opportunity to cover most of Nevada and some of eastern California, and having such widespread coverage was helpful to look at drought impacts.

I mentioned above that we appeared to be seeing impacts of the drought on the Black-throated Sparrows in our IMBCR surveys.  During the season, it seemed I was detecting fewer of them, and when I was, it seemed there were more at higher elevations than “normal,” and further north.  Talking to Ned, he, too, was seeing them in greater numbers on his more northern surveys.  So I did a quick data dive – I didn’t look at elevation, so I can’t say whether my initial impressions were correct in that regard, but we certainly did see some changes in latitude!  The following quick video shows the results of three years of our BLM surveys – the numbers are detections of Black-throated Sparrows within 100m, summarized at the transect level, but to maintain consistency between years, I only used data from points that were surveyed in each of the three years: 2019, 2020, and 2021.  We can see that there’s a fair amount of annual variation in those numbers, but that there was a clear tendency for fewer detections overall, and fewer detections in southern Nevada.

 

The total abundance (of all species) was even clearer on these surveys, declining over the three-year period, with the steepest drop in 2021, where total detections (tallied as above) in 2021 were 25% lower those in 2019.  Here’s how those results were visualized.

 

 

So, it was an interesting year for us, and we are looking forward to seeing what 2022 holds!  Stay tuned for our next installment ….

- Jen