Herring Gull

A regular breeding resident and migrant; regular in the winter and especially common along Lake Superior. The Herring Gull was an uncommon species during the Minnesota Breeding Bird Atlas (MNBBA).

The Herring Gull has a circumpolar distribution; its’ North American breeding distribution extends from Alaska, southeast across Canada, to the Great Lakes and north Atlantic coast. In southern Canada and the northeastern United States, breeding densities are highest along the Atlantic coast, from Newfoundland south to the Delmarva Peninsula, with local concentrations at several inland sites, including the Great Lakes (Figure 1).

Assigned a Continental Concern Score of 11/20 by Partners in Flight and designated a species of Low Concern by the North American Waterbird Conservation Plan.

A short- to medium-distance migrant that winters along coastal waters throughout North America and Mexico. Birds also winter in the southeastern United States and the Caribbean Islands.

Gleans food from the ground, from aerial plunge dives, and from surface dipping while swimming. An omnivore that feeds on a wide variety of animals, including aquatic invertebrates, fish, insects, young birds, and eggs. Also scavenges on garbage, carrion, and refuse from fishing and other vessels.

A shallow cup nest usually placed on the ground but occasionally found on cliff ledges; frequently nests in large colonies, often with other colonial nesting species, but may be found as isolated pairs or in very small colonies numbering less than 10 pairs.

Northern Minnesota is on the southern periphery of the Herring Gull’s breeding range. The gull is a common resident on the rocky islands that dot the inland waters of Lake of the Woods and border the North Shore of Lake Superior. Nearly 100 years ago, Roberts (1932) described it as a common spring and fall migrant throughout the state but largely restricted to those two large water bodies during the breeding season. The birds were also common during the winter months on Lake Superior when the lake did not freeze. At the time, a small number of nesting records were available from islands in Lake of the Woods (Gull Rock, Big Oak, and Four Block, each in 1915) and from two localities along the North Shore. The latter included an island near Two Harbors, which most likely was Knife Island (1923), and Two Islands in Taconite Harbor in Cook County, which today is known as Bear Island and Gull Island (1905; J. Green, pers. comm.).

In the years that followed, the nesting colony on Knife Island was regularly censused by the Duluth Bird Club, who published reports on their field visits from 1941 through 1952. When Roberts (1932) first identified the site as a nesting colony in 1924, only 25 nests were found. During the time that the Duluth Bird Club visited the colony, it grew from 73 nests in 1941 (Jones 1942) to 312 nests in 1950 (Hofslund 1950). The last report, in 1952, reported only 150 nests.

Elsewhere, in 1945, nearly 150 nests were found on an island just north of Beaver Bay along the North Shore by Olga Lakela and Evelyn Jones (Jones 1945). In 1966, Herring Gulls were reported nesting on Lake Mille Lacs (Huber 1966). Unfortunately, just a few years later, in 1970, only 1 nest was found on the lake’s Spirit Island, while none were reported on Hennepin Island (Ivanovs 1971).

In the 1970s, the arrival of Ring-billed Gulls to the Duluth-Superior Harbor led to increased efforts to survey and census the harbor’s gull and tern populations. The first reported nesting of Herring Gulls in the harbor was in 1973, when a single nest was found within the first major nesting colony of Ring-billed Gulls at the 27th Avenue West taconite dock area. Although the entire colony failed (Harris and Matteson 1975), Herring Gulls have continued to nest in the harbor in small numbers (usually less than 50 pairs) and always in association with Ring-billed Gulls (Davis and Niemi 1980; Bracey, pers. comm.).

In 1975, Green and Janssen provided a more thorough account of the species’ statewide distribution, writing that it was found nesting along the rocky islands that bordered the North Shore of Lake Superior, along the border lakes from Lake of the Woods east through Cook County, on Lake Vermilion, and occasionally on Lake Mille Lacs. Although the large border lakes and Lake Vermilion often supported colonies numbering 100 or more pairs, smaller lakes usually supported only isolated pairs or small colonies.

Overall, the largest colonies occurred along the North Shore. Indeed, this was confirmed several years later when Goodermote (1980, 1984, 1989) conducted a series of surveys along the shore, from Knife Island north to the Canadian border. Between 1978 and 1979 he inventoried 84 sites; 37 supported major rookeries, which accounted for 97% of the Herring Gull nesting population along the lakeshore. The average number of nests during the two years was 6,334. The estimate rose to 7,748 in 1984 and 9,037 in 1989 (Goodermote 1984, 1989). The largest populations were located on the Suzie Islands in Cook County, Taconite Harbor in Cook County, Silver Bay in Lake County, and on Knife and Encampment Islands in Lake County.

Farther west, Hirsch (1981) documented 332 nesting pairs on six different islands in the Minnesota portion of Lake of the Woods, and Mortensen and Ringle (2007) documented the history of Herring Gulls nesting on Leech Lake beginning in 1983. Although the birds have consistently been present on Leech Lake’s Gull Island every year but one, the nesting population has always been small, usually numbering 5 to 20 pairs.

Throughout the summer months, nonbreeding adults and immatures may be seen near large lakes across the state, but nesting populations remain confined to northeastern and north-central Minnesota. Janssen (1987) documented 7 northern counties where nesting had been confirmed since 1970: Cass, Cook, Koochiching, Lake, Lake of the Woods, Mille Lacs, and St. Louis. This number remained unchanged when Hertzel and Janssen (1998) provided an updated list of county nesting records several years later. Field staff with the Minnesota Biological Survey have identified 66 breeding season locations confined largely to the Arrowhead region with a few scattered records in Itasca and Beltrami Counties (Minnesota Department of Natural Resources 2017).

During the MNBBA, observers reported 346 Herring Gull records in 4.5% (212/4,741) of the surveyed atlas blocks and in 4.3% (101/2,337) of the priority blocks. Breeding evidence was confirmed in 31 blocks (Figures 2 and 3; Table 1). The birds were reported in 23 of Minnesota’s 87 counties and were confirmed nesting in 7 counties. Although the gulls were not reported in Koochiching County during the MNBBA, as documented by Hertzel and Janssen (1998), they were reported nesting in 1 new county. Young were observed in a nest on Pelican Lake in Crow Wing County in 2010.

The Herring Gull is an adaptable species. There were at least 2 reports of gulls nesting on building rooftops in the city of Duluth: 1 pair nesting atop buildings in the Miller Mall shopping area in the summers of 2009 and 2010; and several pairs nesting atop the Essentia Building in downtown Duluth in 2012, where they continued to nest in 2013 and 2014 (Green, pers. comm.).

Nevertheless, the core of the species’ breeding range in Minnesota remains the North Shore of Lake Superior and the northern lakes from Lake of the Woods east throughout northern St. Louis, Lake, and Cook Counties, similar to that described by Roberts 100 years ago. Elsewhere within the Herring Gull’s breeding range, the only notable change has been the southern extension of their breeding range along the Atlantic coast. Originally limited to Maine and Nova Scotia, they expanded south to the Carolinas between 1910 and the 1960s. Occasional nesting has also been reported in southern Louisiana (Nisbet et al. 2017).

*Note that the definition of confirmed nesting of a species is different for Breeding Bird Atlas projects, including the definition used by the Minnesota Breeding Bird Atlas, compared with a more restrictive definition used by the Minnesota Ornithologists’ Union. For details see the Data Methods Section.

In the Great Lakes, nesting Herring Gulls are typically associated with islands, including both natural islands and rocky islets and artificial dredge-spoil islands (Figure 4). Occasionally marshy hummocks and beaches also are used. Sites that are well drained with rocky or sandy substrates are preferred, as are sites that are open with sparse vegetation, allowing visibility from all directions. The most important requirement for a suitable nest site is protection from terrestrial predators. Sites that provide some vegetation are more successful. Vegetation provides a degree of cover from weather and predators (Nisbet et al. 2017; Wires et al. 2010).

Although Herring Gulls frequently nest in large colonies, it is not uncommon to find them nesting as solitary pairs or in very small colonies numbering less than 10 pairs (Cuthbert and Wires 2013). This is common especially on small lakes, on offshore rocks, and on building rooftops.

Herring Gulls travel up to 100 km from the nesting colony to feed, and most foraging occurs in open water on fish, crustaceans, mollusks, and other waterbirds. A scavenger as well, the Herring Gull has adapted to feeding on a variety of human refuse, including bycatch from fishing boats, garbage in landfills, and livestock feed at agricultural facilities (Nisbet et al. 2017).

In 2002, the North American Waterbird Conservation Plan estimated the population of Herring Gulls as 246,000 breeding individuals (Kushlan et al. 2002). Several years later, the estimate for the Great Lakes Region (the Boreal Hardwood Transition Region), which includes the Laurentian Mixed Forest Province of Minnesota, was 49,600 pairs, or approximately 100,000 individuals (Wires et al. 2010). A recent assessment in 2017 generated a higher continental breeding population estimate of 120,000 pairs nesting along the Atlantic coast, approximately 70,000 pairs nesting in the Great Lakes, and approximately 7,500 pairs nesting elsewhere in Canada and Alaska, generating a total of nearly 200,000 breeding pairs (Nisbet et al. 2017).

A single, statewide population estimate is not available for Minnesota. Nonetheless, an approximation can be made using a series of reports in recent years. The most current data are available from Cuthbert and her colleagues, who began periodic surveys and censuses of American White Pelican and Double-crested Cormorant colonies in the state in 2004–2005 in cooperation with the Minnesota Department of Natural Resources. Because Herring Gulls nest in similar localities, their reports include an account of their nesting status as well. In their most recent survey, in 2015, a total of 2,047 nests were reported at 8 nesting localities. The largest colony was located on Knife Island with 1,536 nests (Hamilton and Cuthbert 2016).

Although Lake of the Woods, Leech Lake, and Lake Mille Lacs were all included in the 2015 survey, sites in the Duluth Harbor, along the North Shore of Lake Superior north of Knife Island, and on many of the northern border lakes were not included. Using recent data collected on all of the Great Lakes from 2007-2012 (Cuthbert and Wires 2013), the North Shore islands north of Knife Island supported approximately 2,361 nesting pairs, and in 2016 the Duluth Harbor supported 35 nesting pairs (A. Bracey, pers. comm. 2016) resulting in a conservative statewide estimate of approximately 4,500 nesting pairs. No estimates are available, however, for Herring Gulls nesting on inland lakes in northeastern Minnesota.

The federal Breeding Bird Survey (BBS) is not well suited to monitoring colonial waterbirds but is the only long-term, nationwide monitoring program available. The BBS data show a long-term, significant population decline across North America averaging 3.53% per year since 1966 and 2.58% from 2005 to 2015 (Sauer et al. 2017). Although less statistically reliable than the national data, data from Minnesota also demonstrate a long-term decline of 3.59% from 1967 to 2015 (Sauer et al. 2017). Since Minnesota’s breeding population is confined to the Laurentian Mixed Forest Province, the status of the population in the Boreal Hardwoods Transition region, which spans the northern Great Lakes states and provinces, is a good indicator of the status of Minnesota’s population. Here, BBS data demonstrate a significant annual decline of 2.55% (Figure 5).

At the regional level, a more precise accounting of Herring Gulls has been undertaken on the Great Lakes by the U.S. Fish and Wildlife Service and the Canadian Wildlife Service. The two agencies have cooperated since the late 1970s in a large-scale effort to monitor colonial waterbirds nesting throughout the Great Lakes. Conducted once every 10 years, the census demonstrated that Herring Gull numbers in the U.S. portion of the Great Lakes have oscillated between a low of 29,833 nesting pairs in 1977 to a high of 44,565 in 1989–91 (Figure 6; Cuthbert and Wires 2013). The increase observed between the last two census periods is due largely to an increase in the number of nesting pairs at several large colonies in Green Bay and on northern Lake Michigan. The authors noted that the species is unique among colonial waterbirds nesting in the Great Lakes because it often nests in small colonies (less than 10 pairs) and is consistently found nesting at more sites (229 in the last census) than any other colonial waterbird.

Overall, Herring Gull populations have recovered significantly from a low in the 1800s and early 1900s, when the birds were shot for their feathers and eggs were collected for food. Subsequent protection of the birds through the Migratory Bird Treaty Act helped spur their recovery, as did the availability of supplemental food sources, including waste at landfills and at coastal fishing ports. The relative importance of these factors, however, is not well documented (Nisbet et al. 2017). Much of the increase along the Atlantic coast was observed from the 1930s to the 1960s, and populations have exhibited declining trends in numbers since then. A decrease in commercial fishing along the Atlantic coast may be contributing to their decline, as may an increase in predatory species such as Great Black-Gulls and Bald Eagles (Nisbet et al. 2017). In the Great Lakes, significant population increases occurred in the late 1960s through the 1980s and were attributed to exploding populations of the alewife (Scharf and Shugart 1998). Since then, numbers in the Great Lakes also have declined though at a much slower rate than observed along the Atlantic Coast (Nisbet et al. 2017). Some have speculated that increasing competition with Double-crested Cormorants for suitable nesting sites may be contributing to local declines (Mortensen and Ringle 2007).

Although there is some indication of declining population levels in recent years, the Herring Gull is not considered a high conservation priority. The North American Waterbird Conservation Plan designated the species a Low Concern in 2002 (Kushlan et al. 2002). More recently it has been assigned a moderate Continental Concern Score of 11/20 by Partners in Flight (2017).  Concern regarding population declines was the most significant influence on the score.

At some sites in the Great Lakes, Herring Gull numbers are controlled due to property damage, but by and large such efforts are minimal across its breeding range and have had limited impact (Cuthbert and Wires 2013; Nisbet et al. 2017). As for many colonial waterbirds nesting in the Great Lakes, contaminants and human disturbance are considered the primary threats (Wires et al. 2010). Organochlorines, in particular, have been documented to cause mortality in embryos and chicks, retard chick growth, and cause deformities. Levels of such contaminants, however, have declined significantly since they were first measured in the mid-twentieth century (Nisbet et al. 2017).

Warming temperatures are predicted to reduce the Herring Gull’s winter habitat 55% by the year 2080. This, coupled with other changes to its breeding range led to its classification as a “climate endangered” species (Langham et al. 2015; National Audubon Society 2016). Given these challenges, continued monitoring of the Great Lakes population, which includes the North Shore of Lake Superior, the core of the Herring Gull’s breeding range in Minnesota, will provide critical, long-term data for monitoring the species in the coming years.