Monitoring Maine’s Great Blue Herons – Three Years and Counting…

Photo by Ron Logan

View a slide show of photos taken by staff, volunteers, landowners, and other partners.

Introduction

Since 2007, the great blue heron (Ardea herodias) has been listed inMaine as a Species of Special Concern.  While this status has no regulatory significance, is does signify possible decline and that more information is necessary to accurately determine the population trend.  Thus, an effort was initiated in 2009 to better track great blue heron colonies and the number of nesting pairs in the state, both on coastal islands and at inland sites.

HERON Volunteer View: Great Blue Herons Caught on Video

Photo by Deb Dutton

June is when nestlings appear in most great blue heron colonies in Maine.  In Maine, great blue herons lay their eggs anytime between late April and mid-May.  After approximately 27 days of incubation, the nestlings hatch out mostly unfeathered except for pale gray down that appears a bit bushy on the crown.  They weigh less than 2 ounces at hatching and can barely hold their heads up.  Within a week or two they can be seen poking their heads above the edge of the nest bowl, especially when their parents return to the nest to provide food.  Within 7-8 weeks, the nestlings will grow to adult size, weighing in at 4.5 lbs and standing about 3 ft tall.  Check out a video clip of a heron nest with nestlings taken by Deb Dutton on Facebook!

HERON Volunteer View: FOOD FIGHT

An adult great blue heron arrives ready to feed its nestlings. Photo by Ron Logan.

 [The short article and incredible photos below are from volunteer, Ron Logan, who monitors 4 great blue heron colonies for HERON.]

The season will begin in a couple weeks to monitor my 4 Great Blue Heron colonies. These pictures are from last year and were taken from quite a distance. Generally you can’t get very close to nests, since they are in wetlands and 20 to 50 feet in the air.  If you think feeding your babies was tough, or that dinner table fights with your siblings was a nightmare, imagine what it would be like as a Great Blue Heron.

Heron Watchers Needed

In April 2009 at this colony in downeast Maine, ice-out is not yet complete and the herons have yet to return. Photo by Jonathan Mays.

The snowpack is gradually receding at my house.  A remnant of our first snowman of the winter is poking its head out once more (so that’s where my hat went!).  While I dread the looming mud season that will follow, I am excited that spring is really on its way.  In fact, the Vernal Equinox is just around the corner: March 20^th to be exact.  Besides mud season, the arrival of spring also marks the return of great blue herons to Maine.  Have you seen any herons yet?  Feel free to post here or on Facebook to share your first heron observations of the season.

Hear About Herons

Great blue heron. Photo by Ron Logan.

The great blue heron is often touted as one of the most widespread and adaptable birds in North America.  Here in Maine they are certainly widespread, but recent data has suggested a decline in their breeding population especially along the coast.  Concerns over a population decline prompted the Maine Dept. of Inland Fisheries and Wildlife to conduct a comprehensive survey of breeding colonies in 2009, and to begin a statewide adopt-a-colony program called the Heron Observation Network.  Join me at one of the following locations to learn more about Maine’s largest colonial wading bird…

 

Volunteers, Landowners, and the Public Help Make 2nd HERON Season a Success

[About the image above:  This great blue heron was made by my father, Sam D'Auria, out of several different hardwoods, an art form called intarsia.]

As 2010 draws to a close, I’d like to take a few moments to thank all those who have helped to make the 2nd year of the Heron Observation Network a success.  To date, I’ve received data from 41 volunteers who monitored 52 great blue heron colonies in 2010.  These volunteers contributed 148.5 hours of their time to increase our understanding of the status of the great blue heron in Maine.  THANK YOU!  In addition, members of the public reported more than 13 new colonies, thereby increasing our ability to track the statewide population.  Many thanks to all the landowners who have provided staff and volunteers access to their land for the purpose of monitoring great blue heron colonies.  Not only are the landowners providing access, but they are also providing in one way or another disturbance-free habitat that is appealing to herons for nesting.

I’ve enjoyed meeting and communicating with our volunteers and landowners, and look forward to additional interactions in the coming year.  There are always more colonies that need volunteer monitors and there are likely more colonies to be discovered.  If you know of a wading bird colony, please don’t hesitate to report it to me.  Or, if you’d like to join the Heron Observation Network and adopt a colony yourself, please contact me, danielle.dauria@maine.gov, (207) 941-4478.

Best Wishes for a Happy and Healthy New Year!

Sebasticook Valley Middle School Outdoors Club Adopts Great Blue Heron Colony

Logan Labree, Dalton McCaughlin and Rachel Bates measure and record the diameter of a great blue heron nest tree while Skip Walsh (in background) searches for another nest.

On a brisk fall afternoon after most students have headed home from Sebasticook Valley Middle School, 10 students remain.  They each don a hunter orange cap supplied by the school and head outside.  Today’s meeting of the Maine Outdoors Club is a unique one.  They have two guests: Brad Allen and I, both biologists with the Maine Department of Inland Fisheries and Wildlife (MDIF&W).

Though it is hunting season, the students are not going to learn about hunting laws or ethics.  Instead, they will assist with monitoring a great blue heron colony located literally in their back yard, right on school property.

The school district’s great blue heron colony was originally reported to MDIFW by local residents in 2009.  The initial ground visit by biologists last April revealed only six nests, but the breeding season had just begun and the colony was likely not yet fully occupied.  An aerial survey of the site in late June revealed an estimated 30 nests, most containing nestlings.

Nondirectional Wandering Brings Southern Birds North to Maine

Cattle egret observed feeding on grasshoppers on Bailey Island in Harpswell. (Photo by Jonathan Mays)

Fall is upon us and winter is certainly not far behind.  [Snow was flying as early as Halloween at my house this year!]  As the cold weather moves in, herons typically move out…of Maine, that is.  I say typically because there are definitely stragglers here and there.  But, what’s more interesting is that after herons breed they typically disperse in all directions before heading south for the winter.  In the scientific literature, this is dubbed “nondirectional wandering.”  This is why we can see such rarities as yellow-crowned night-herons and cattle egrets in the fall in various parts of the state.  We don’t currently have either of these species nesting in the state – at least not that I am aware of.  And they certainly are not known to breed north of Maine.

Get the Lead Out for FREE

A radiograph of a common loon showing a lead sinker (the brightest white object) in its gizzard. Photo courtesy of Avian Haven.

 

One of my not-so-glamorous duties as a wildlife biologist in our agency’s Bird Group is to collect dead loons and send them to the Tufts School of Veterinary Medicine’s Wildlife Clinic to be necropsied (a necropsy is an autopsy of a wild animal).  Dr. Mark Pokras and his students determine the cause of death as part of an ongoing study, and then let me know so I can inform the concerned citizen who originally notified me or a coworker of the dead loon.  I just finished cataloguing, bagging, and freezing 2 loon chicks and 5 adults.  With the help of Avian Haven, a wild bird rehabilitation facility in Freedom, we were able to get radiographs of a few adults – 2 individuals showed obvious lead sinkers in their gizzards.  These were both adults, most likely breeding adults, that were otherwise healthy.  A sad twist of fate presented them a lead sinker instead of an ordinary stone to add to the numerous stones already in their gizzard used for grinding food.  It doesn’t take much lead to cause lead poisoning, and death is only a few days away. 

Heron Trash Can Be a Researcher’s Treasure

Remains found beneath heron nests. Clockwise from top left: egg shells and membranes, crayfish claw and fish backbone, fused rear vertebrae and pelvis (from 3 different aged herons), heron feathers, heron skull and mandible, leg and wing bones.

Did you know that you can learn a lot by what is on the ground at the base of a heron’s nest tree?  A heron nest is only so big, so there’s no room for food remains and other forms of heron “trash”.  Herons simply just pitch it all over the edge.  Out of sight, out of mind, I guess.  Light blue eggshells with some membranes in tact indicate a successful hatch; but you may also find remains of young herons that met their premature demise by falling to the ground.  Adult feathers that were molted are often found.  You might find out that crayfish is a favorite food of the family above.  This disposal area for the herons nesting above can really be a treasure trove to a researcher trying to find out how dam removal affects the birds that use a river.