We have a resident great blue heron that we watch every summer and have affectionately named “Harry.” He hangs out on a rock that is exposed when the tide goes out a little bit and snakes his long neck out over the water, inspecting it for signs of fish. We did a little research to figure out whether our friend was a male and found out that herons are somewhat unusual in that the males and females don’t have distinctive differences in coloration or size. We kept his name nonetheless. Because Harry often lands in the same place throughout the season and from year to year, we also always assumed that he is the same bird. But, how would we really know?
Herons do often pick feeding sites that they return to repeatedly, so it seemed plausible. They sometimes even defend a site from other birds, claiming it as their own, solo feeders that they are.
But, the real way to tell if Harry is the same bird from last week or last year is to tag him. That’s what a project headed by the Department of Inland Fisheries and Wildlife (IFW) has been doing. What they have found through tagging is not just who is who in the local heron population, but what their movement patterns are like along our coast as well as much further afield.
The herons being studied are Great Blue Herons, Ardea herodias. They are the biggest and heaviest of the herons – a group of birds that includes other herons like the Black-Crowned Night-Heron as well as egret species like the Great Egret and the Snowy Egret. They all have long legs, heavy bodies, and long bills for catching fish. The Great Blue Heron can be as tall as 4 ½ feet, stretch their wings as wide as 6 ½ feet and weigh up to 8 pounds. Their distinctive blue-gray color gives them their name and makes them fairly easy to identify.
While many of us were hunkered down during the 2020 pandemic, herons were on the move. It turns out they don’t hang out near the same places all year, but instead, can fly great distances to reach warmer weather during the winter. In October of 2020, IFW tracked a female heron, Harper, that they had tagged in 2019. Her flight path stretched an impressive 2,030 miles between Quebec and Georgia. It turned out that she had flown 68 hours nonstop during her migration – breaking the record she had set the previous year of a 38-hour stretch straight over open ocean! She was on her way to spend the winter in her southern habitat.
Scientists were able to figure out all these details via a transmitter in her tag that relays data back to their computer. It’s a little bit like a Fitbit in the way it records speed and distance. It also tracks records like maximum speed – 60 miles per hour for Harper – and height – up to 4100 feet! This is much higher and faster than a heron hanging out in one place for the season. There are all kinds of amazing graphics showing this data on the IFW website (www1.maine.gov/wordpress/ifwheron/). You can also access much more data on a website called Movebank that connects directly to Harper’s transmitter. You can take the information from here and put it into Google Earth to see where she is. Instructions on how to access this are on the IFW website.
So, what does this tell us about Harry? Harper has certainly been on the move. But, this is not the case for all great blue herons that live in Maine – and possibly not for Harry. Some don’t migrate as long as they can find enough open water with food through the winter. We won’t likely be tagging Harry, particularly given our hunch that he’s a local. But, IFW is hoping to capture and tag another great blue heron in the Harpswell area this spring.
This is a neat community science opportunity for anyone interested. IFW has been working with the Harpswell Coastal Academy and a team of dedicated volunteers. They are keeping eyes out for where herons are foraging both in person and through game cameras that can provide insights about what is happening when they are not there. Volunteers also help to capture bait fish and stock bait bins that are used to attract herons in a variety of locations.
In addition to the tagging work, volunteers keep track of great blue heron colonies across the state as part of the citizen science program, the Heron Observation Network. In 2020, 68 volunteers and staff made 200 visits, driving over 4,343 miles to monitor 112 great blue heron colonies. If you are interested in being involved, please contact Danielle D’Auria at danielle.dauria@maine.gov or (207) 485-8386. Or, just check out the project blog to learn more about the project, to follow Harper’s path, and to keep tabs on whether a new Harpswell heron will be sending data back from his or her travels.
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