Featured mission: Surveying Eared Grebes at Mono Lake

Mono Lake in November 2022 as seen from a LightHawk flight provided by VP Wayne Sayer. Foam from the alkine water makes counting Eared Grebes challenging. Photo credit Robbie Di Paolo, Restoration Field Technician MLC.

Each fall LightHawk provides flights for the nonprofit Mono Lake Committee (MLC), located in Lee Vining, California. Since 2008, more than 30 LightHawk flights have enabled the Mono Lake Committee to participate in an ongoing research project to study the Eared Grebe (Podiceps nigricollis), a migratory waterbird. According to Robbie Di Paolo, MLC's Restoration Field Technician, over 90% of the entire North American population of Eared Grebes use Mono Lake or Great Salt Lake in Utah as staging areas to molt their body and wing feathers after their breeding season. The fact that almost the entire North American population of Eared Grebes concentrates at two geographically restricted sites is highly unusual for any migratory species, making them an ideal candidate for monitoring outside of breeding season.

VP Wayne Sayer providing a flight for Mono Lake Committee while conducting an Eared Grebe survey in November 2022. Photo credit Robbie Di Paolo, Restoration Field Technician MLC.

Critical requirements for completing successful surveys include an aircraft with a high wing so the view is not obscured, and an open window for photography. Additionally, the conditions of Mono Lake need to be calm enough to assure visibility of Eared Grebes in photos.

Before the flight, LightHawk volunteer pilot Wayne Sayer met MLC's Restoration Field Technician, Robbie Di Paolo at Lee Vining Airport (O24). It was a clear and cold day with a temperature of -3° C. Robbie had been to the lake shore earlier in the morning to assess the calmness of the water, and confirmed the conditions with Wayne. The flight was good to go!

View of the landscape surrounding Mono Lake from a LightHawk flight provided by VP Wayne Sayer. Photo credit Robbie Di Paolo, Restoration Field Technician MLC.

The aerial photography and surveys from LightHawk flights has been invaluable for ongoing research conducted since 1996. Robbie recently reached out to LightHawk about two findings from a published paper from December 2020 he contributed to titled Abundance, Distribution and Migration Patterns of North American Eared Grebes (Podiceps nigricollis). Robbie specifically noted critical pieces of information that inform MLC moving forward:

1). Conducting multiple flights from late-August to mid-November is critical to understanding Eared Grebe timing and numbers at Mono Lake. Previously it was thought that one mid-October flight would sufficiently characterize Eared Grebe visitation to Mono Lake, but resulting data had inexplicable spikes and dips between years. Multiple surveys in subsequent years, which were made possible thanks to LightHawk, have allowed us to demonstrate that peak abundance timing can be inconsistent. Future research will seek to further characterize trends in the migration to Mono Lake utilizing multi-flight methodology.

2). The surveys suggest a strong correlation between the number and timing of Eared Grebe at Mono Lake and the number and timing of brine shrimp (Artemia monica) in the lake. Enhanced inland aquatic research will now be conducted at Mono Lake on an annual basis to provide better shrimp counts and better inland aquatic analysis overall. This enhanced research will have great potential to help us better interpret and understand Eared Grebe numbers from our aerial surveys.

We're grateful to VP Wayne Sayer, and all the pilots who have generously provided flights for the Mono Lake Committee, and the ongoing critical Eared Grebe conservation research! The Mono Lake Committee is dedicated to the restoration of Mono Lake and recognizes Eared Grebes as one of the bird species of special significance due to the historical and current reliance on Mono Lake. Mono Lake Committee acknowledges the important role volunteer pilots provide and are planning additional Eared Grebe surveys in 2023.

MLC capturing Eared Grebes to retrieve band and geolocator tags at Riske Creek in British Columbia, Canada. Photo credit Mono Lake Committee.