New paper uses data gathered by citizen scientists to study Osprey feeding rates

June 2022

An Osprey with outstretched wings holding a fish takes off from a wooden perch. There are trees and snow-capped mountains in the background.
Charlie, the male Osprey at the Charlo MT nest, takes a large bass to his mate Charlotte (on a different nesting platform).


An academic paper about Osprey feeding rates and nesting success includes data gathered by citizen scientist live cam viewers- including those who watch ORI’s Osprey cam! "Use of Nest Web Cameras and Citizen Science to Quantify Osprey Prey Delivery Rate and Nest Success" was recently published in the Journal of Raptor Research (ORI was not involved in this analysis). This study was only made possible by the effort of Osprey live cam viewers from around the world- thank you all for your dedication and hard work helping to observe and record fish deliveries to the nest!


This study is the first to use data collected from citizen scientists from a worldwide network of Osprey nest web cameras. They used data from 19 nests total, located in North America and Europe. Two of the nests included are in Montana: ORI and Explore.org’s Osprey live cam (here in Charlo, MT) and the cam at Dunroven Ranch in Lolo, MT. Observations included in the study were conducted from 2014 to 2020.


Observers recorded information including: the number of fish delivered to the nest each day; the number of chicks; and the final outcome of the nest (if the Osprey pair was successful in raising healthy chicks, or if the chicks or young Osprey died).


The study found that 74% of the Osprey nests were successful, and 26% failed. One key finding: successful nests have significantly more fish delivered per day, with low variation in the number brought each day. For the nests in this study, those with an average of 3 or more fish per day were more likely to be successful. Nests that failed had fewer fish coming in, and a lot more variability in when those fish were brought to the nest.


In other words: a steady stream of fish brought to the nest means that a nest is more likely to be successful.


There are many factors that can influence the hunting and nesting success of Osprey. Many are natural, like weather, fish populations, or natural disasters like flooding. For example, the recent catastrophic flooding of the Yellowstone River in Montana has huge impacts on the wildlife that rely on that habitat. Osprey can’t fish when the rivers are too high, fast, and murky. (See this 2018 Montana Public Radio piece about our friends and collaborators at the Montana Osprey Project: Clark Fork Osprey Struggling After Spring Floods, Researchers Say and this Vox article from 2022: How Yellowstone’s animals survive a catastrophic flood).


However, some of those factors are caused by humans. The Montana Osprey Project has been studying heavy metal contamination in Montana’s upper Clark Fork River and its tributaries.


Another issue that impacts nesting Osprey is baling twine. Read more, and learn about what you can to do help clean up baling twine, on ORI’s website: Danger in the nest: Osprey and baling twine.


 

More information about this study

Title:

Use of Nest Web Cameras and Citizen Science to Quantify Osprey Prey Delivery Rate and Nest Success


Authors:

Michael H. Academia and Harmony J. Dalgleish


Abstract:

Ospreys (Pandion haliaetus) are obligate piscivores and their nesting success depends on sufficient amounts of fish delivered to the nests during the breeding season. Nests are considered successful when pairs raise a minimum of one young to fledging or near-fledging age. Through web cameras and online broadcasts of Osprey nests, citizen scientists quantified daily number of fish deliveries, nest survival, and nest success. We received and analyzed curated data (one to seven seasons, 2014–2020) from citizen scientist groups representing 19 Osprey web cameras from four countries in North America and Europe. We compared the average and the coefficient of variation of the number of fish delivered per day within the early breeding season between the failed and successful nests using a Wilcoxon rank-sum test. We