By 1808Delaware; Special to 1808Delaware
The Ohio Department of Natural Resources has issued an update on bald eagle nesting surveys conducted in 2022.
In the spring, the ODNR Division of Wildlife completed its annual survey. The survey consists of flying five blocks that are roughly 10 square miles each and looking for eagle nests in woodlots and along rivers. Two of the blocks, which are located around Sandusky Bay (Ottawa/Sandusky counties) on Lake Erie and Mosquito Creek Wildlife Area (Trumbull County) in northeastern Ohio, are flown every year, while the other three are rotated every year.
In 2022, the other three blocks were located around Big Island Wildlife Area (Delaware/Marion/Union counties), around Walborn Reservoir (Portage/Stark counties), and along the Muskingum River (Muskingum/Morgan counties). The survey is initially conducted in March to search for nests when eagles are incubating eggs. A follow-up survey is done in May to determine the number of young produced in active nests.
Biologists found a 2% increase from 2021 in the number of eagle nests, based on the survey of nests within the sample areas in March. This results in an estimate of 824 eagle nests within the state for 2022. After several years of tremendous growth rates ranging between 7% and 29%, the lower increase in nests may indicate a density-dependent slowing and stabilization of the state’s breeding bald eagle population. However, productivity rates determined from the May survey were much lower than in previous years. Only 47.8% of nests were successful in 2022, and the number of young per active nest was 0.8, which for the first time since 2009 was below the number of 1 eaglet per nest needed to sustain the population. Highly pathogenic avian flu was confirmed in the state in March of 2022, and several deceased bald eagles tested positive for the disease. An unprecedented number of eagle deaths were noted throughout northern Ohio during March and April, and it is likely that avian flu was the primary cause of the reduction in nest productivity.
Disease is known as a population regulator, and when populations reach carrying capacity this is often a major regulating factor as opposed to other sources of mortality (such as a lack of food or other resources). Biologists will continue to closely monitor the bald eagle population and the impacts of avian flu. However, the bald eagle population has been robust in recent years, and staff remain optimistic that the population will recover from the impacts of avian flu in the coming years. In addition, of the successful nests this year, 1.6 fledglings were produced, which is a number similar to previous years. Some pairs were able to continue business as usual, and the hope is that the coming years will allow for a greater number of pairs to regain their normal levels of productivity.
The Division of Wildlife will continue to work with other agencies and rehabilitators on monitoring the impacts of avian flu and continue to enforce protective state and federal laws such as the Bald and Golden Eagle Protection Act to ensure the ongoing success of the bald eagle.
