State College Bird Club Meeting
October 28, 2020
Online Zoom Meeting

Presiding:  Doug Wentzel

Recording: Peggy Wagoner Saporito

Attendance: 40

Treasurer’s report (Jean Miller): $304 spent on logo redesign; $235 received in dues. (Mail-in dues are still being accepted, see website)
Zoey Greenberg, membership chair, commented on the impressive support and enthusiasm for the bird club within the State College community.

Announcements:

 Thanks to Nick Kerlin, for his tireless dedication during the past ten years, as bander-in charge of bird banding at the Arboretum Avian Education Program.

The new logo is completed and ready for use. Thanks to Susan Smith, Nick Bolgiano and Jon Kauffman who worked with designer, Alissa Pendorf.

 

Jen Lee is nearly finished with the checklist update that will include the new bird club logo.

Thanks to Jim Dunn, who will be stepping down this year, for his contributions during the past 18 years as primary complier of the State College Christmas Bird Count. Bob Fowles will continue in the role of co-complier. Email Doug if you are interested in either serving on a committee to find the next compiler, or if you would like to be considered for the primary complier position.

Although there are no field trips scheduled at this time, the Christmas Bird Count is coming up on December 20 in both Huntingdon and Centre counties.

Interesting Bird Sightings: Greg Grove’s Summary

Greg highlighted a number of interesting and unusual sightings in the area since late September, including scoters, shorebirds, warblers and the arrival of fall sparrows and winter finches including some Evening Grosbeaks. Greg reminded us that dreary, rainy autumn days are the times we should head to places like Bald Eagle State Park and Lake Perez to view “fallouts” of waterfowl unable to continue their fall migration until the weather clears. At the Stone and Jacks Mountain hawk watches there have been good flights of Accipiters (3rd highest year for Sharpies at Stone) and falcons, including good numbers of Kestrels. There have been record low numbers of Osprey however. Golden Eagles have begun to migrate and should continue to be seen at hawk watches through November on those blustery west-to-northwest windy days.

Speaker: Brandon Hoenig: Stream Bugs Make Strong Birds: The importance of aquatic prey for the development of nestling Louisiana Waterthrush

(This entire presentation can be viewed here)

Brandon, a PhD candidate at Duquesne University in Pittsburgh has been studying Louisiana Waterthrush (LOWA) at Powdermill Nature Reserve in Westmoreland county.  By combining traditional field research with lab-based techniques, Brandon has been studying the impacts of prey availability on both nestling and adult LOWA and implications for long-term conservation.

Considered a bioindicator species, this wood warbler prefers healthy forested streams and nests directly in stream banks. Waterthrush rely heavily on aquatic insect prey such as stoneflies and mayflies which are higher in fatty acids as compared to terrestrial insects such as moths and true flies. Even when nestlings are fed lower quantities of fatty-acid-rich stoneflies and mayflies, they have greater mass than young that are fed larger quantities of terrestrial insects.

Stonefly and mayfly populations are known to be lower to non-existent in poor quality acidified streams such as those impacted by abandoned mine discharge. Studies have shown that more breeding pairs are found in high quality streams, and nestlings have longer wings and greater body mass than those raised in acidified stream habitats. Brandon compared impacts of high quality vs. acidified stream habitats on nestling diets and development as well as adult LOWA  behavior.

Multiple fecal sacs from 5-7 day old nestlings were used to extract prey DNA to determine which insect species nestlings were being fed and to estimate frequency of occurrence. Stable isotope analysis was used to determine the percentage of each prey species in the diet of each nestling. As anticipated, diets of nestlings raised in high quality habitats were dominated by high quality prey – primarily mayflies and stoneflies. In acidified stream habitats, lacking mayflies and stoneflies, nestlings’ diets consisted of a variety of lower quality terrestrial prey species. As a result body condition of nestlings in high quality streams areas was better than those raised in acidified stream habitats.

The behavior of adult LOWA is also impacted by availability of prey species. Mayflies are more prevalent early in the season which can help explain why waterthrushes are among the first migrants back on breeding grounds. LOWA begin establishing territories as early as mid March to take advantage of early aquatic insects.

Brandon found differences between early (mid May) vs. late (mid June) broods reflecting prey availability.  In early broods, mayflies made up 75% of nestling diets and only 50% of diets in late broods. Later broods had more terrestrial insects represented in their diets. Duration of foraging trips (time adults spent away from the nest to find food for nestlings) averaged 7.5 minutes for early broods and increased to 10 minutes in later broods. This indicates that parent birds may be having more difficulty finding prey later in the season when mayflies are not as prevalent. The adults may have to travel further afield to find prey. In addition, early broods typically have 5-6 nestlings whereas later broods have 3-4 nestlings.

This research, focusing on impacts of insect prey on the health and behavior of a bird species, highlights the importance of considering prey in avian conservation efforts. The fact that both LOWA and trout require healthy streams with an abundance of the same aquatic arthropods could lead to collaboration between fishermen and birders in efforts to support these habitats. In addition, broader implications of climate change resulting in seasonal shifts in bird and prey insect phenology were briefly discussed.