Snowy Plover Activity in the Central Platte River Valley in May 2019

During five of eight site visits between 14 and 27 May 2019 we detected up to four Snowy Plovers (Charadrius nivosus nivosus) in the Central Platte River Valley (CPRV) near Mormon Island, Hall County, Nebraska, and recorded their behavior using an instantaneous scan sampling approach. We recorded loafing (47%), foraging (43%), mating (4%), flying (4%), and external threat (1%) related behavior. Most notably, we documented a copulation event on 23 May. During the 10-day span from 14 to 23 May when Snowy Plovers were detected, river stage and discharge were near median levels, but from 23 to 27 May river discharge more than doubled and gage height increased by over 20%. This resulted in sandbar habitat becoming submerged and the Snowy Plovers vacating the site. This observation illustrates how wide variation in late spring flows can preclude potential breeding by ground nesting waterbirds in the CPRV given the current limited availability of unvegetated sandbars significantly exceeding flood stage. This represents a notable late-spring stay length in the CPRV with behavior suggestive of the potential for local breeding

New Wilson’s Phalarope Nesting Record from the Central Platte River Valley, Mormon Island, Hall County, Nebraska

The southeastern portion of the Wilson’s Phalarope’s (Phalaropus tricolor) breeding range encompasses parts of Nebraska (Colwell and Jehl 1994), including the Sandhills and northern Panhandle (Silcock and Jorgensen 2018). Additionally, there have been a number of breeding records from southcentral and southeastern Nebraska within the Rainwater Basin ecoregion since the mid-1990s (Mollhoff 2016, Silcock and Jorgensen 2018). However, there is very little evidence of regular breeding activity in the nearby Central Platte River Valley (CPRV), which spans from Chapman west to Overton, Nebraska, and is considered a globally important area for waterbirds (Johnsgard and Brown 2013, Silcock and Jorgensen 2018). Sutton and Arcilla (2018) documented two juvenile Wilson’s Phalaropes with two adults on 28 June 2017, confirming successful breeding in the CPRV on Mormon Island, Hall County, Nebraska. However, Sutton and Arcilla (2018) did not document an active nest and therefore lack a detailed description of the nesting habitat used by Wilson’s Phalaropes in this unique ecoregion. On 6 June 2019 we found a Wilson’s Phalarope nest while walking between avian point count stations on Mormon Island, 4.7 km northwest of Doniphan and 14.4 km southwest of Grand Island, Nebraska, on land owned and managed for the benefit of migratory birds by the Crane Trust (https://cranetrust.org/). The landscape is managed with rotational grazing and prescribed fire to simulate natural disturbance regimes (Fuhlendorf et al. 2009). Mormon Island contains the largest contiguous tract of wet meadow remaining in the CPRV (Currier and Henszey 1996, Brei and Bishop 2008). Mormon Island consists of about 1075 hectares (ha) or 2,656 acres (ac) of primarily relict and restored wet meadow and lowland tallgrass prairie habitat, and exists within a complex of 2,425 ha (5,992 ac) of land protected for conservation purposes along a 13 km (~8 mi.) stretch of the Platte River. The nest was found when an adult male Wilson’s Phalarope flushed directly off the nest from the ground at a distance of approximately 3 meters (m) from approaching observers

Landscape-Level Long-Term Biological Research and Monitoring Plan for the Crane Trust

Our obligation is to make sure we are effectively utilizing science to meet the objectives of the Platte River Whooping Crane Maintenance Trust (1981) laid out in its charter “to rehabilitate and preserve a portion of the habitat for Whooping Cranes and other migratory birds in the Big Bend reach of the Platte River between Overton and Chapman (i.e., Central Platte River Valley), Nebraska”. The original declaration is aimed at maintaining “the physical, hydrological, and biological integrity of the Big Bend area as a life-support system for the Whooping Crane and other migratory species that utilize it.” It was clear from the institution’s founding that to accomplish this goal it was necessary to study the effectiveness of land conservation and management actions in providing habitat for Whooping Cranes and other migratory bird species. Quality habitat necessarily comprises all the components that Whooping Cranes and other migratory bird life require to complete their migrations –food and shelter– including nutrient rich diet items such as invertebrates, vascular plants, herpetofauna, fish, and small mammals as well as suitable roosting and foraging locations including wide braided rivers and undisturbed wet meadows (Allen 1952; Steenhof et al. 1988; Geluso 2013; Caven et al. 2019, 2021). Article “A” of the Crane Trust’s (1981) declaration is “to establish a written habitat monitoring plan which can be used to describe change in…[habitat] within the Big Bend of the Platte River…utilized by Sandhill Cranes and Whooping Cranes….” Following initial inventories including avian (Hay and Lingle 1982), vegetation (Kolstad 1981; Nagel 1981), small mammals (Springer 1981), herpetofauna (Jones et al. 1981), insects (Ratcliffe 1981), and fish (Cochar and Jenson 1981), a variety of excellent research has continued at the Crane Trust (https://cranetrust.org/conservation-research/publications/). However, despite the clarity of the Trust’s original declaration, long-term habitat monitoring has not progressed unabated throughout the history of the Crane Trust.https://digitalcommons.unl.edu/zeabook/1130/thumbnail.jp

Biological Case Against Downlisting the Whooping Crane and for Improving Implementation under the Endangered Species Act

The Whooping Crane (Grus americana; WHCR) is a large, long-lived bird endemic to North America. The remnant population migrates between Aransas National Wildlife Refuge, USA, and Wood Buffalo National Park, Canada (AWBP), and has recovered from a nadir of 15-16 birds in 1941 to ~540 birds in 2022. Two ongoing reintroduction efforts in Louisiana and the Eastern Flyway together total ~150 birds. Evidence indicates the U.S. Fish and Wildlife Service (USFWS) is strongly considering downlisting the species from an endangered to a threatened status under the Endangered Species Act (ESA). We examined the current status of the WHCR through the lens of ESA threat factors, the USFWS’s Species Status Assessment (SSA) framework, and other avian downlisting actions to determine if the action is biologically warranted. Our research indicates that WHCRs are facing an intensification of most threat drivers across populations and important ranges. The AWBP is still relatively small compared to other crane species and most birds of conservation concern. To date, only one avian species has been downlisted from an endangered status with an estimated population of \u3c3,000 individuals. Representation in terms of WHCRs historic genetic, geographic, and life history variation remains limited. Also, the lack of spatial connectivity among populations, reliance of the reintroduced populations on supplementation, and continued habitat loss suggest that WHCR populations may not be resilient to large stochastic disturbances. Given that reintroduced populations are not self-sustaining, neither supplies true redundancy for the AWBP. Proposed downlisting before recovery plan population criteria have been met is objectively unwarranted 3 and reflects USFWS inconsistency across ESA actions. Only by incorporating basic quantitative criteria and added oversight into ESA listing decisions can we avoid an action as misguided as downlisting the Whooping Crane without consideration of its recovery plan criteria or ostensibly its population ecology

Snowy Plover Activity in the Central Platte River Valley in May 2019

During five of eight site visits between 14 and 27 May 2019 we detected up to four Snowy Plovers (Charadrius nivosus nivosus) in the Central Platte River Valley (CPRV) near Mormon Island, Hall County, Nebraska, and recorded their behavior using an instantaneous scan sampling approach. We recorded loafing (47%), foraging (43%), mating (4%), flying (4%), and external threat (1%) related behavior. Most notably, we documented a copulation event on 23 May. During the 10-day span from 14 to 23 May when Snowy Plovers were detected, river stage and discharge were near median levels, but from 23 to 27 May river discharge more than doubled and gage height increased by over 20%. This resulted in sandbar habitat becoming submerged and the Snowy Plovers vacating the site. This observation illustrates how wide variation in late spring flows can preclude potential breeding by ground nesting waterbirds in the CPRV given the current limited availability of unvegetated sandbars significantly exceeding flood stage. This represents a notable late-spring stay length in the CPRV with behavior suggestive of the potential for local breeding

Habitat associations and activity patterns of herpetofauna in the Central Platte River Valley, Nebraska, with notes on morphometric characteristics

The Central Platte River Valley (CPRV) is a unique and biologically important ecoregion, and several studies have conducted localized herpetofauna species inventories. However, there has been significantly less effort to quantify the habitat associations or activity patterns of these species. Habitat associations and activity patterns vary regionally and provide important information for ecosystem management. We deployed a total of 38 traps of 5 different types (pitfall, funnel, hoop, box, and coverboard) across 11 sites (7 terrestrial, 4 aquatic) for an 8-week period in June and July 2019. Our exploratory analyses used generalized linear models with a quasibinomial distribution to examine associations between herpetofauna abundance (captures per trap night) and habitat characteristics controlling for trap type. Habitat characteristics assessed included distance to nearest woodland, distance to nearest standing water, vegetation species richness, soil texture, and vegetative cover in addition to others. We also evaluated activity patterns weekly across the study period. The two most abundant species demonstrated divergent distributional patterns, Northern Prairie Skinks were only absent from two of the driest terrestrial sites, while the Six-lined Racerunners were locally abundant at just three sites with significant bare ground and sandy soils. We documented a Cope’s Gray Treefrog at a site with little woody cover in which the species had not been previously observed, suggesting it may be increasingly widespread regionally. We also detected relatively widespread juvenile anuran dispersal at multiple terrestrial sites a considerable distance from standing water. Our results provide a preliminary examination of habitat associations and summer activity patterns for herpetofauna in the CPRV that can be used to inform conservation efforts and further studies of this system