A view from above looking at water

Eared Grebe research at Mono Lake

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 species’ historical and current reliance on Mono Lake. Since 2008, the Mono Lake Committee has collaborated with Dr. Sean Boyd from Environment and Climate Change Canada to facilitate annual aerial Eared Grebe surveys at Mono Lake. As of December, 2021, this work is now published in the scientific journal Waterbirds.

The Mono Lake Committee coordinates multiple aerial surveys each fall to determine the number of Eared Grebes at Mono Lake. Photo by Robbie Di Paolo.

There are two findings from the paper that are critical pieces of information for the Committee moving forward. The first finding is that conducting multiple aerial survey 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 Eared Grebe migration to Mono Lake using this established multi-flight methodology.

During each flight, Robbie, the Committee’s Restoration Field Technician, photographs Mono Lake’s surface methodically so that the grebes in the photos can be counted. The grebes appear as tiny dots—see the top photo. Photo by Robbie Di Paolo.

The second finding is that the surveys suggest a strong correlation between the number and timing of Eared Grebes at Mono Lake and the number and timing of brine shrimp (Artemia monica) in the lake. While annual shrimp counts have been conducted in the past, enhanced limnological research will be conducted at Mono Lake on an annual basis starting in 2022 (thanks to State Water Board Order 21-86), which will provide better shrimp counts and better limnological analysis overall. This enhanced research will therefore have great potential to help us better interpret and understand Eared Grebe numbers from the aerial surveys.

Additionally, there is a unique opportunity to quantify the entire North American Eared Grebe population due to their concentrated migratory staging at Mono Lake and Great Salt Lake. The Utah Division of Wildlife Resources has also been conducting aerial surveys at Great Salt Lake for Eared Grebes using a similar methodology adapted from the aerial surveys at Mono Lake. These surveys may therefore provide valuable information about the total North American Eared Grebe population, as well as valuable context for the counts here at Mono Lake.

Dr. Sean Boyd with a banded Eared Grebe in Riske Creek, British Columbia, the northern part of the grebes’ migratory range. Photo by Robbie Di Paolo.

All in all, there is a lot of great research being done on Eared Grebes in North America with plenty of new technology and research opportunities on the horizon and the Committee is excited to be playing a critical role in that body of work. Moving forward, the Committee plans to continue to work with Dr. Sean Boyd, the lead researcher conducting aerial Eared Grebe surveys at Mono Lake.

Top photo by Robbie Di Paolo.