The earliest known studies of the island are by Redfield (1883, 1893) who did brief floras of the island. Unfortunately Redfield makes no comment on the island’s overall flora or fauna, apart from a brief mention of a “sheep grazed area”.

Early accounts of the island’s avifauna are somewhat sparse, but it is clear that Great Duck was regarded as an important nesting site for the then seemingly endangered Herring gull (Larus argentatus) in the late 19th century. It is important to note that many published estimates seem to be based on quick approximations rather than systematic counts, and it is not always clear (even within an article) whether an author is referring to birds or nesting pairs. The early estimates prior to Gross’ 1922 survey are particularly suspect. Counts from 1985 on have been adjusted upwards by a 15% “correction factor” for missed nests (Drury 1973).

Dutcher (1901, 1905) seems to have visited the island several times as part of early work in bird protection. At some point between 1898 and 1900 Dutcher seems to have arranged for the lighthouse keeper to assume the role of warden, protecting first the gulls on Great Duck, and subsequently also those on Little Duck. The island was visited by Bent (1921) in 1904 as part of his overall studies of North American Birds, but he also cites a later visit by a Maj. G. Ralph Mayer (or Meyer) who visited the island on June 20, 1913 to study the Herring gulls. The bulk of several sections of Bent’s Life History for the Herring gull is in fact taken from Mayerís apparently otherwise unpublished notes. It should be noted that whereas Mayer has a number of detailed comments about nesting behavior, his estimate of 4000 pairs does not seem to be the result of a systematic search, and later in the piece he talks of seeing 4000 gulls.

Mayer also mentions large numbers of dead trees on the island and the gulls nesting in amongst the broken stumps. The implication is that the gulls killed the trees, and Mayer mentions that 3 trees were in fact being used as “nesting trees”. Several authors have suggested that the gulls took to nesting on tree-limbs in order to escape human predation. This is somewhat hard to accept as an explanation given the obvious nature of a tree-nest. It seems more likely that if the gulls were in fact nesting in trees it was to escape domestic animals brought by the light-keepers or the livestock men. It should also be noted that our earliest accounts to date begin just after the keepers are appointed to protect the gulls, so it is likely that the birds moved around the island as the effects of protection took hold.

It is perhaps significant that Dutcher and Baily (1903) say specifically, “On the southern end of the island nearly all the trees have been cut and the dead tops and branches, together with many large trunks, have been left among the stumps!” (emphasis added). The “dead trees” in later accounts may in fact be referring to this human-created tangle. Photographs in Dutcher and Baily’s article show both dead and living standing spruce immediately above the berm line at the southeast end of the island. At the risk of raising an unsupportable hypothesis, the devastated area described by Mayer and also later by Gross (below) is strikingly similar to that common in double-crested cormorant (Phalacrocorax auritus) colonies, although none were supposedly nesting in Maine in the late 1800’s/early 1900’s (Knight 1908).

Drury (1973) gives a figure of 5000 pairs for the island in 1920. Drury includes it in a table dealing with a number of Maine islands, and the data appear to have been derived from multiple sources (probably Norton and Allenís field notes). Gross (1922) visited the island in the summer of 1922 and conducted a systematic count of the entire island over the course of July 1-2, which should correspond to peak nesting. Like Mayer nine years earlier, Gross reported that the bulk of the gulls were nesting at the south end of the island in or near the light station grounds, and that the spruce trees at that end of the island were mostly dead - presumably killed by the large quantities of guano. If Drury’s figure is to be believed, the colony declined by nearly two thirds in just two years - in spite of what Gross describes as the continuing protective role of the Light keeper.

Pettingill (1984) visited the island in 1929 as an undergraduate student of Gross. Unfortunately Pettingill’s report was not written until more than 50 years after the fact, was published in a popular magazine, and in fact bears a striking resemblance to some parts of Gross’ earlier paper. Pettingill does not seem to have performed an island-wide count, but instead mentions “5000 birds”. If we take this figure at face value and correct it according to Drury’s (1973) 1/1.5 correction factor for nesting pairs, we arrive at 3333 pairs - a dramatic comeback over Gross’ estimate of 1246 pairs in 1926.

The importance of these numbers lies particularly in Drury’s next estimates (again apparently from un-published sources) of 300 pairs in 1930 and 600 in 1940. Clearly SOMETHING happened on the island (it is worth noting that according to Drury, Little Duck’s population went from 750 pairs in 1920 to 4000 in 1930, raising the possibility that birds on Great Duck moved to Little Duck as the result of some sort of disturbance. Further analysis of these numbers may be found in the Discussion section (below). From 1930 on, Little Duck continues to have a larger population of Herring Gulls than Great Duck.

Lesser (1977) conducted a limited survey of the island’s flora and fauna as part of a more intensive study of Little Duck Island. Folger and Wayne (1986) undertook a more detailed study in 1985 as a report to The Nature Conservancy upon the Conservancy’s acquisition of portions of the island. Since that time Greene (pers. comm.) has conducted sporadic additional studies of the island’s vegetation, and an amended flora is forthcoming. In 1991-3 Ron Butler of the University of Maine Farmington and his students conducted studies of the island’s guillemot population and also censused gulls. More recently Butler has conducted surveys of lichens at the island’s north end.

A survey of the literature makes it clear that Great Duck Island has been a major nesting site for the Herring gull (Larus argentatus) for over a century. In addition, the island supports one of the largest - if not the largest - populations of nesting Leach’s storm petrels (Oceanodroma leucorhoa) in the eastern United States. Finally, boat counts and research by Butler (pers. comm.) suggested that the island supported a significant proportion of the total black guillemot (Cepphus grylle) population in Maine waters.