What is the Colonial Waterbird Survey?

The Colonial Waterbird Survey is a statewide survey facilitated every 5 years by the State of Massachusetts. The last survey was done on island in 2018. The purpose of the Colonial Waterbird Survey is to keep track of the birds’ breeding and nest count to properly protect species and their habitats. 2024 is the first year that all states in the Atlantic Flyway (states from FL-ME along the East Coast) are participating during the same time frame and using the same formatting to conduct their survey. This will give a larger insight into migration patterns for these coastal waterbirds. The waterbirds nests counted on Nantucket are Snowy Egrets, Great Egrets, Black-crowned Night Herons, Yellow-crowned Night Herons, Double-crested Cormorants, and, those whose nests we see the most by far, the Herring Gulls and the Great Black-backed Gulls. In fact, in past years, Nantucket has had the largest population of Herring Gulls in all of Massachusetts. The properties included in the survey are owned by NCF, TTOR, Mass Audubon, and the US Fish and Wildlife Service (end of Great Point). Having to cover so much land calls for a group effort from the NCF staff and the other organizations mentioned; this survey could not be completed without lots of patience and support. The survey is not quite done yet, but it is coming to an end after the immense amount of progress made within the past few weeks.

The Process:

To properly prepare, we put our hats on and our hoods up as the Gull parents can be very protective over their nests and chicks (and rightfully so!). We gather in a straight line about an arm’s length apart so we can get a proper visual of all the nests in our path. As we walk, we keep tallies of how many nests we see per species. In the middle of May, we started at Great Point, working with the Trustees on their properties, and in that location alone, the Trustees reported that we tallied over 500 more nests than the last survey. The total from Great Point this year was 316 Great Black-backed Gulls and 737 Herring Gull nests. To count a nest in the tally, it must be either a nest full of eggs, a nest with some chicks nearby, or a nest that has clearly been used recently (eggs remains, feathers, etc). When we come upon a Gull nest, it can be difficult to tell which species the eggs belong to. The Herring Gull eggs tend to be pointier in shape, but the most certain way to tell is to alternate between looking up to see what Gulls might be sitting on nests around you and then quickly looking back down to watch where you step to avoid disturbing any nests or chicks.

In the middle of May, it was also assumed that if a nest had chicks, it belonged to a Great Black-backed Gull as they tend to nest earlier and therefore their chicks hatch earlier in the season. Recently, there have been lots of chicks running around of all sizes so it is better to use other strategies. The main strategy used was that the bird flying above the nest is usually of the same species. To tell the difference between the Herring Gull and the Great Black-backed Gull, we reference wing color. The Herring Gull’s wing is a light shade of gray while that of the Great Black-backed Gull is a darker, almost charcoal gray. Of course, when the parent birds dive bomb you to make sure you keep a safe distance from their offspring, it is with almost 100% certainty you know what species that nest belongs to! The total count of nests (including nests with eggs and empty nests with chicks nearby) on Coatue were 193 Great Black-backed Gulls and 447 Herring Gulls. This leads to a grand total of 509 Great Black-backed Gull nests and 1,188 Herring Gulls! Keep in mind that there are about 3 eggs per Gull nest which equals a lot of baby Gull chicks!

A baby Gull chick exploring the beach

The Gulls can all be found along the dunes and grassy landscapes of the beach, but this is not the case for all shorebirds. Cormorants build nests in the same terrain as Gulls do, but they nest in very large colonies. The Cormorant colony on Coatue has up to 572 nests this year whereas in 2018, there were only 150. Still on Coatue, but moving away from the beach and dunes, we ventured into the areas of trees to count the Heron and Egret nests. It quickly became an other worldly experience. In order to find the nests, we had to crawl through a forest of Red Cedar trees and look for the tell-tale sign of a large white spot on the ground. Look up, and there’s the nest! It was almost impossible to know which nest belonged to which bird unless you saw the chicks peeping out. I write “chicks”, but these babies are large, almost muppet-like birds which only added to the strange experience. We had a team outside of the forest watching what birds flew up from the trees as we walked through to get a good estimate. By the end of the day, we had such great stories to share, that the group designated as our watchers ventured in to see for themselves.

Cormorant chicks and parents at the colony on Coatue

The days are filled with lots of walking up and down the beaches, but even when there are only a few sightings, we enjoy each other’s company and find lots of ways to have fun. It never gets old discovering a nest and each time we do, it feels like winning a game similar to an Easter egg hunt! We all love to compare our steps at the end of the day (usually between 10 and 15 thousand) and take time to laugh during lunch breaks. There is always a smile on everyone’s face and when someone finds something cool, we all quickly group around to see an egg that is hatching that very moment or new fluffy chicks hiding in a bush. The survey has been a great chance for all members of the NCF staff to participate, not just the Wildlife team. The Botany, Ecology, and Education teams have all had their chance to learn about the process and it certainly helps to have as many people as possible as there is a lot of beach to cover! Thank you to all those who have helped so far! Keep an eye out for more to come as the survey comes to an end. Updates can be found on our social media platforms: @ackconservation

Written by Meredith Broadus, Seasonal Field Assistant

Top: a Gull hatching from its’ egg Bottom Left: Newly born cormorants Bottom Right: Egret chicks

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