Radio-tracking Delaware Wood Thrushes to aid their conservation

Ian Stewart

The Wood Thrush (Hylocichla mustelina) is one of our most iconic woodland birds yet unfortunately it is in steady decline and is listed as a Species of Greatest Conservation Need in several states, including Delaware. In 2024, US Fish and Wildlife launched an ambitious range-wide, full-cycle tracking study to understand the causes of this decline, in which Wood Thrushes were fitted with radio-transmitters on their breeding grounds then followed using the Motus network of automated receiving stations (www.Motus.org). Given enough tagged birds, it should be possible to identify the stages in their annual cycle associated with the greatest losses (breeding season, migration, or non-breeding season). This was a huge success, with 572 Wood Thrushes tagged in over 20 US states and 1 Canadian province. Thanks to support from Delaware Audubon as well as donors and partners, Delaware was well represented, and we were able deploy transmitters on 26 birds (20 adults and 6 juveniles). This gave us interesting data on the timing of their migration, which we found to be later than expected. Most birds left our area in mid-September, but some remained through mid-October. 23 of our 26 tagged birds (89%) made it out of the state, and the majority of these were detected several states away (13 in Georgia, plus several in the Carolinas and Florida). One of them was detected in Belize, Central America, and several more may have made it to the non-breeding grounds but are not within range of an automated Motus station. We are excited to see the results of data uploads from these stations and also how many birds are detected when they migrate north this spring.

Construction and installation of 100 nest boxes for use by secondary cavity nesting birds in New Castle County

Catherine Woodfield

The goal of this project is to install 100 birdboxes in New Castle County, mainly for Eastern Bluebirds, but also for Tree Swallows, Chickadees, and Wrens. Thirty birdboxes were previously installed at Middle Run, Newark De at a reforestation site, which have shown success over two seasons, with 41 nesting sites, 90 nesting attempts, 342 eggs, 257 young, and 220 fledglings. Working with Joe Sebastiani from the Delaware Nature Society, we received permission to place birdboxes at two new sites on Polly Drummond Road, south and north of the original location, featuring a mix of meadow and wooded areas, including a pond and a reforestation project. The boxes will be installed by mid-March, with similar positive community feedback expected. The University of Delaware Birding Club plans to visit, and 15 boxes will be donated to start a Bluebird trail on the UD campus. Additionally, 5-6 boxes will be donated to a local middle school whose boxes are in disrepair.

Using genetic sequencing techniques to study avian malaria parasites in American kestrels across Delaware

Laura Kwasnoski

American kestrels (Falco sparverius) are North America’s smallest falcon and are listed as a Species of Greatest Conservation Concern in the state of Delaware due to population decline. Factors ranging from pesticides to habitat loss have been implicated in contributing to kestrel decline. However, few researchers have considered how kestrels are impacted by infectious disease.

I studied the prevalence and diversity of malaria parasites in Delaware kestrels. Avian malaria is a disease vectored by biting insects and is common in birds around the world. I used molecular methods to screen kestrels from across Delaware for these parasites and compared my results with data from another kestrel population in Utah and to previously published scientific literature. I found that 31.4% of Delaware kestrels were infected by parasites in the genus Haemoproteus. These parasites have previously been found in the United States, Mexico, and Uruguay. The Delaware and Utah kestrel populations were largely infected by the same parasite species.

The results of this project contribute to a baseline understanding of the prevalence and diversity of avian malaria parasites in Delaware kestrels as well as parasite ecology in kestrels overall. This provides context for understanding the causes of parasite distribution and infection risk, particularly in threatened species like kestrels already undergoing population decline.

Piglet Bugs! Investigating the Species-level Classification of A Charismatic Insect of Conservation Concern and the Description of a New Species From Delaware.

Solomon Hendrix

The goal of this project was to diagnose and describe two species of grassland-endemic piglet bugs from the United States. Piglet bugs (Hemiptera: Auchenorrhyncha: Fulgoroidea: Caliscelidae)—affectionately named for the often snoutlike projection of their heads and stout bodies—are a relatively obscure group of small herbivorous insects notable for their diversity in the native grasslands of North America, a highly threatened ecosystem. One species of piglet bug, Fitchiella robertsonii, represents the only planthopper in the United States with state-level conservation status. However, the species has not been assessed throughout most of its range, which extends (in the east) from Florida north to New York and (in the west) from Texas north to Minnesota.

Specimens identified as this species were found in the Smithsonian National Collection, collected in Arizona, which would be a significant range expansion for this species of concern. We determined, through morphological study, that these specimens actually represented the very poorly-known piglet bug Bruchomorpha rugosa. Based on the clear affinities of Bruchomorpha rugosa to Fitchiella robertsonii, we transferred the species to Fitchiella and an amended diagnosis was written. Photographs were taken or obtained of all Bruchomorpha and Fitchiella species. Additionally, a new species of piglet bug in the genus Bruchomorpha was discovered and described from Delaware which is found sparsely in grassy areas across the midatlantic. This new species was compared to museum specimens for diagnosis; this review of Bruchomorpha and Fitchiella resulted in the discovery of several additional new species and taxonomic issues which may be addressed in future work.

The results of this project have increased our understanding of an obscure group of charasmatic insects that live within a highly threatened ecosystem. With completed photographic guides of two genera, a renewed assessment of an obscure species, and the description of a new species, we have set the stage for future work on the group, which will be crucial to future conservation efforts targeting American grasslands, especially arthropod diversity assessments. We intend to continue the work initiated by the conservation grant as we have barely scratched the surface when it comes to the diversity of this enigmatic family of insects in the United States.