State College Bird Club Zoom Meeting
November 18, 2020

Presiding: Doug Wentzel

Recording: Peggy Wagoner Saporito

Attendance: 33

Treasurer’s report (Jean Miller): $50 spent on last month’s presenter; $130 received in dues. (To send your annual dues by mail, see website)


Next spring, Millbrook Marsh Nature Center will be hosting socially distanced weekly bird walks at their facility beginning March 23. Doug Wentzel and Jon Kauffman will be leading some of these walks, but additional volunteers are needed. Anyone interested in leading walks, please contact Doug.

The Pennsylvania Game Commission will soon be working to improve Woodcock habitat in Stone Valley. Commission officials indicated that Stone Valley is one of the best areas of the state in terms of woodcock numbers and habitat potential.

Thanks to Jen Lee for volunteering to be State College Christmas Bird Count compiler. She will be working with Bob Fowles who continues as co-compiler. And thanks to Greg Grove for recruiting Jen.

Christmas Bird Counts in the area have been set. For more information, see Audubon’s 121st CBC: Map of Active Circles

December 19 Penns Creek (including Penns Valley) (Cathy Pierce)
December 20 State College (Jen Lee and Bob Fowles)
December 20 Huntingdon (Deb Grove)
December 27 Bald Eagle State Park (Bob Snyder)
December 28 Lake Raystown (Jon Kauffman)

Interesting Bird Sightings: Greg Grove’s Summary
(late Oct-mid Nov)

Fall migration is winding down but eruptions of Northern winter finches are ramping up with many reports of Evening Grosbeaks, some Red Crossbills and Redpolls. There are still a few shorebirds around and 11 different warbler species were reported during the period including unusual sightings such as Orange-crowned, Tennessee and Common Yellowthroat. Some encouragingly high counts of Rusty Blackbirds have been reported. Marsh Wrens, Tree and Fox Sparrows have also been around in somewhat higher than usual numbers. At the hawk watches, Golden Eagles have been passing through, concentrated on days with strong northwest winds, and even a few Rough-legged hawks, which are more typically seen later in winter, have already been reported in the area.

Speaker: Allison Cornell: “Life in the Nest Box: Nestling development in American kestrels”
(This presentation (missing the first minute) can be viewed here).

Allison, now an assistant professor of Biology at PSU Altoona, described work she had recently conducted in Eastern Pennsylvania, in collaboration with Hawk Mountain Sanctuary and Cedar Crest College, to study American Kestrel nestlings in nest boxes located on farms with suitable short grass and pasture habitat.

American kestrels are of concern because number of adult pairs and percent nest box occupancy has dropped 50-60% since the early 1990’s in the 100+ nest boxes monitored by Hawk Mountain staff. Apparently, the number of fledglings that survive to adulthood, to raise chicks of their own, has declined over time. Habitat loss, predation by Cooper’s hawks, West Nile Virus and lower overwinter survival have all been speculated in this decline.

By studying nestling development and subsequent fledgling health and survival, population declines can begin to be addressed. Nestlings of all species face challenges as they achieve developmental milestones, particularly when transitioning from nestling, a sedentary lifestyle, to fledgling, a very active lifestyle. Mortality rate is high among many different species during the first month after fledging, often due to predation.

Survival and reproduction is influenced by an animal’s behavior, morphology, physiology and biochemistry. To study some of these factors, Allison focused on morphology and physiology of nestlings as well as parent behavior in terms of prey delivery to chicks.  She monitored nests in 2018 and 2019 during the first 3 weeks of nestling life prior to fledging, which occurs during the 4th week.

Prey delivery by parent birds was monitored with cameras located just outside of nest boxes. Early in the season, rodent and passerine prey dominated and later in the summer, arthropods such as crickets and grasshoppers, constituted a larger portion of chicks diets.

Nestlings’ weight increased quickly, approaching adult weight, during the first 2 weeks, then plateaued prior to fledging. As with adults, female nestlings tended to be somewhat heavier than male chicks. Feather growth in both sexes, as shown by wing chord length, progressed linearly until fledging.

To monitor chick physiology, weekly blood samples were drawn to measure hematocrit and hemoglobin levels. As nestlings prepare for fledging, transitioning to an active life of flight requiring greater aerobic capacity, higher hematocrit and hemoglobin levels would be expected. However, of the 58 chicks monitored, there was no clear pattern; hematocrit and hemoglobin increased in some and decreased in other nestlings over the 3 week blood monitoring period. It is unclear what is causing these variations. Nestling diet may be a factor.
Allison is planning on studying this in greater detail with a supplemental feeding study. By manipulating nestling diets, Allison hopes to understand how diet impacts nestling development and subsequent fledgling health and survival.