Wood: Colonial nesting birds of the Norwalk Harbor, CT

 Chris Wood

Chris researched the colonial nesting birds of the Norwalk Harbor area for his Master’s thesis in the late 1970’s and will summarize that historical status of those bird populations.  

Broker: Winter population trends in LIS birds

 Steve Broker

Early Winter PopulationTrends in Long Island Sound Birds

Connecticut Christmas Bird Counts, 1970-2021

Presenter:  Steve Broker

Connecticut Christmas Bird Count data for the Long Island Sound coastline were reviewed for the 52-year period 1970-71 through 2021-22.  The eight coastal counts range from Greenwich-Stamford in the west to Napatree, RI/NY/CT in the east. Six of these eight coastal counts have been conducted each year since 1970, some of them first held many years earlier than 1970.  Two coastal counts have been added to our LIS shoreline in more recent years.  The early winter populations of Long Island Sound birds have seen significant increases for some bird species and major declines for others, as indicated in a series of graphs.    

Ellis: Osprey Nation

Elphick: Intro to University of Connecticut presentations

Gigliotti: Testing the Efficacy of Saltmarsh Restoration

Testing the Efficacy of Saltmarsh Restoration for a Globally Endangered Species

Franco Gigliotti, Chris Elphick

Saltmarsh ecosystems are changing, with evidence of marsh loss as sea levels rise. Breeding bird species, including the saltmarsh sparrow Ammospiza caudacuta, that depend on these ecosystems are likewise declining. Restoration will be a necessary component of conservation for these species, and thin layer placement of sediment (TLP) has garnered interest as a restoration tool. Saltmarsh sparrows require high-elevation marsh habitat for breeding, but benefits of restoration will only be realized if TLP restored marsh generates nesting habitat and restoration does not negatively impact nest success. We worked with Stewart B McKinney NWR, Audubon Connecticut, and other partners to assess impacts of TLP on saltmarsh sparrows using constructed TLP hummocks (n=14) each with multiple vegetation treatments (n=5) at Great Meadows Marsh (GMM). Preliminary results indicate that (1) sparrows nesting in unrestored areas at GMM and at a reference site both exhibited high rates of nest failure, (2) hummocks achieved target elevations to promote marsh plant regeneration, and (3) initial vegetation growth on hummocks varied by treatment. These results indicate baseline hummock conditions following sediment addition. Data in subsequent years will inform saltmarsh sparrow nest success, nest site selection, and space use following TLP, enhancing understanding of the efficacy of TLP to reduce nest failure, a main cause of decline for this threatened species.:

Eswarakumar: Effects of invasive plants on the tidal marsh

Effects of the Invasive Plant, Phragmites australis, on Tidal Marsh Insect Communities and its Dietary Repercussions for Saltmarsh Birds. 

Saltmarsh sparrow and seaside sparrow diet in salt marshes in coastal Connecticut.

Carlin Eswarakumar  and Chris Elphick

University of Connecticut

I intended to study the relationships between the invasive saltmarsh grass, Phragmites australis, and various communities in CT saltmarsh ecosystems. I focused my study on insects and insectivorous birds of the saltmarsh. My study aims to answer two main research questions: How does the invasive plant, Phragmites australis, affect the insect community when it replaces the native saltmarsh plant community of Spartina grasses? And how do these resulting changes in the insect community impact endangered saltmarsh sparrows and other insectivorous birds living in the tidal marsh ecosystem? I hypothesized that the introduction of Phragmites australis will displace native insect populations to areas of the marsh where Spartina grasses remain or reduce overall insect abundance. Native insects likely have not yet evolved to obtain their critical shelter or food resources from the significantly different Phragmites plant. I additionally hypothesized that if Hypothesis 1 is correct, Phragmites australis will indirectly affect saltmarsh birds because they will have less prey. Thus, the future status of endangered saltmarsh birds will depend on how much native Spartina grasses remain.

To study this, I compared the insect communities found on the invasive P. australis to three species of native vegetation found in the salt marsh, short form Spartina alterniflora, tall form S. alterniflora, and S. Patens.  I sampled insects at 108 plots of near-isolated patches of each type of vegetation: 36 plots per vegetation type, throughout three different saltmarsh sites, at Sluice Creek in Guilford, Hammonasset in Madison, and Great Meadows Marsh in Stratford. I used two different sampling methods, vacuuming and sweep-netting. The vacuum samples will be sent for DNA identification, known as metabarcoding, while the sweep-net samples will be manually identified with microscopy up to morphospecies within an order. Metabarcoding is a DNA analysis process that identifies unique taxa sequences within a pool of DNA. During the same sampling period, I additionally worked with other lab members to mist-net Saltmarsh Sparrows and Seaside Sparrows and collected fecal samples at the same three saltmarsh sites. These fecal samples will also go through metabarcoding to identify the families of insects the birds are consuming and will show any relationship between insectivorous birds and how their prey selection is affected by the invasive P. australis. The goal at the end of this study is to see if an invasive plant significantly changes the communities of the saltmarsh.

I am still in the progress of completing these goals. I am currently working on insect identification and am awaiting results from the DNA analysis. But I believe this research is important not only because it will give us an idea of how invasive plants affect the at-risk saltmarsh habitat and insight into potential ramifications for marsh restoration, but also provides us with data of insects that are vastly understudied in CT saltmarshes.

DeMott: Radar reflectivity to measure Tree Swallow migration

 Will DeMott

University of Connecticut

NEXRAD highlights the effects of wind and date at a Tree Swallow roost during fall migration

William G. DeMott1, *, Andrew N. Stillman1, James B. Kolb2, and Chris S. Elphick1

1Department of Ecology & Evolutionary Biology, University of Connecticut, Storrs, CT 06269, USA

2Department of History, University of Connecticut, Storrs, CT 06269, USA 

*Corresponding author: will.demott@gmail.com

ABSTRACT — Tree Swallows (Tachycineta bicolor) are migratory aerial insectivores that breed across North America and have experienced long-term population declines. Although the mechanisms behind these declines have proved difficult to identify, emerging methods for studying migration staging areas could provide new insights. Tree Swallows congregate in staging roosts during fall migration, gathering at sunset to roost overnight, then leaving at sunrise to feed or continue their migration south. Using a particularly large roost site in Connecticut, USA, we used NEXRAD Level III data to calculate metrics of reflectivity corresponding to snapshots of morning roost size each day. Using these metrics as measures of relative abundance, we tested predictions about the effects of wind and date on daily roost size and day-to-day changes in relative abundance. We found that radar reflectivity around the roost decreased with higher wind speeds during the morning emergence and when wind speeds were high the previous day. In addition, we found a temporal pattern of roost abundance corresponding to a peak migration season around the end of August for this stopover site.  Our results provide insight into the sensitivity of Tree Swallow responses to wind conditions and lay the groundwork for future studies using NEXRAD to examine links between migratory behavior and declines in swallow populations.