Help Needed for Heron Colony Observation Survey


The Pennsylvania Game Commission has launched its periodic Heron Colony Observation Survey to help improve its ability to monitor heron populations and their distribution in the state.  The survey is focusing chiefly on Great Blue Herons and the state-endangered Black-crowned Night-Herons and Yellow-crowned Night-Herons, all of which are state Wildlife Action Plan priority species. Although many heron colonies have been documented across the Commonwealth, it’s possible that you may know about colonies that we don’t. Your input could improve immediately our understanding of heron populations and nesting colonies, which can change suddenly and have in Pennsylvania. 


Great Blue Herons are listed as a “maintenance concern” species in the Pennsylvania Wildlife Action Plan, because they are a species that is fairly secure in Pennsylvania, but for which the Pennsylvania Biological Survey recommends management attention.  They still are considered abundant and fairly secure and serve as an indicator for high-quality habitats. Yellow-crowned and Black-crowned Night herons are listed as “Pennsylvania vulnerable,” because they are a species most at risk and/or are experiencing the most dramatic declines within Pennsylvania, but are not at risk at the regional, national, or global level.


This survey is not actually new; it’s been conducted periodically for some time. But this appeal is being made because the agency’s ornithologists believe that the website can help spread the word among state’s birding community , as well as the general public, that they’re looking for help to survey the Commonwealth’s more than 46,000 square miles for nesting herons. Together, we can assess the status of Pennsylvania’s current heron populations and create more timely and immediate “snapshot” of the distribution of nesting herons statewide. The information will be used to update the Pennsylvania Natural Heritage Program database and also enable us to better understand the status of these priority species.


Filling out the survey form is a fairly easy undertaking. It helps that herons are pretty interesting and charmingly ungainly and large enough to be easily observed and identified at a distance. Their nests should be monitored with binoculars from a safe distance. Please do not approach nests. For information on the natural history and conservation of night-herons in Pennsylvania, please review the Endangered and Threatened Species Section.


So, if you know where herons are nesting, we’d sure appreciate hearing from you. Don’t assume someone else will report local nests. Download the Heron Colony Observation Data Sheet, fill it out and submit it to Don Detwiler, who is serving as our project coordinator and is managing the survey data. Read the Heron Colony Observation Protocols to ensure you’re approaching this fieldwork in a way that will help science and not disrupt nesting herons and send your completed survey forms to:


We are primarily interested in the location of active nests, the type of habitat they’re found in and the shape or layout of the colony.  The survey also asks participants to document threats to nesting colonies.  Thank you in advance for your willingness to help us with this important survey and to spend time helping our wild birds. Herons can never have too many friends.

Pennsylvania Game Commission, 2001 Elmerton Ave, Harrisburg Pennsylvania 17110-9797