After American white pelicans completely abandoned their nesting colony on Gunnison Island last year, the Utah Division of Wildlife Resources was encouraged to see the birds nesting on Hat Island this year — the first time they have nested there since 1943.
Located in the Great Salt Lake, Hat and Gunnison islands are both owned by the DWR and are designated as wildlife management areas, primarily serving as protected bird rookeries. Both islands have served as important nesting areas for migrating American white pelicans throughout the years because of the isolation and protection they offer the nesting birds. Because pelicans are so susceptible to disturbances, the islands are closed to visitors. It is illegal for people to go within one mile of the islands by land, air or water.
Pelicans are very large birds, so their nesting period takes a long time:
- A week to court, build a nest and lay eggs
- A month to incubate the eggs
- Three weeks to feed a nestling
- Nine to 10 weeks to care for a pre-fledgling
“In total, this process takes about four months or longer, so pelicans need a protected space for a long period of time, and remote islands provide that protection,” DWR Great Salt Lake Ecosystem Program Manager John Luft said.
However, due to low water levels, neither island has actually been an “island” for many years, and predators like coyotes have gained access to the islands via land bridges. Because pelicans are extremely susceptible to disturbances while nesting, eventually the birds stopped nesting at Hat Island — with the last confirmed reports of nesting there in 1943 — and biologists believe they abandoned the Gunnison Island nesting colony last year due to repeated disturbances from predators.
There are several key factors that play a role in where pelicans choose to nest, including:
- Isolation and security
- A reliable and productive food source nearby to supplement their nesting efforts. (The wetland areas around the Great Salt Lake provide an abundant food source for the birds.)
- Pelican habits and nesting site fidelity
“Pelicans are very gregarious birds, and they not only cooperate when feeding, but they also benefit from one another in these nesting colonies,” Luft said.
DWR biologists conduct surveys each year to monitor populations for different bird species that use the Great Salt Lake and its associated wetlands during spring and fall migrations. During surveys on April 29, biologists confirmed that pelicans were again nesting at Hat Island.
“As far as we can tell, pelicans are nesting at Hat Island again because some may be a little ‘gun shy’ about nesting at Gunnison Island after the disturbances that led to the colony abandonment last year,” Luft said. “So this year, some birds decided to find a new location to nest that is still close to the rich food sources in wetlands on the eastern shore of the Great Salt Lake.”
In addition to nesting at Hat Island, biologists confirmed that nesting pelicans are back at Gunnison Island this year, as well.
“Some of the pelicans are breeding for the first time this year, so they didn’t experience the abandonment event last year,” DWR Great Salt Lake Ecosystem Program Wildlife Biologist John Neill said. “Young pelicans take about four years to mature to breeding age, so they likely think that conditions will be similar to what they experienced when they grew up on Gunnison Island four years ago. And because pelicans like to stick together in groups, some of the adult pelicans that nested somewhere other than Gunnison Island last year may have ended up following other pelicans to nest at Gunnison Island this year.”
Because monitoring surveys are still ongoing and the pelicans are continuing to arrive at the nesting colonies, the DWR doesn’t yet have a final count of how many pelicans are nesting on each island. However, initial estimates are around 800 birds on Gunnison Island and around 1,300 on Hat Island. The average number of nests at Gunnison Island over the last 10 years was 4,290, with 8,580 breeding adults. In 2022 and 2023, the Gunnison Island pelican colony only had about 2,900 nests, with roughly 5,800 breeding adults — the lowest number since the 1970s.
“Overall, pelican populations are doing well, and even the total abandonment of the Gunnison Island colony last year had little impact on the continental pelican population,” Luft said. “Seeing birds nesting at both islands again is a good sign that shows the resiliency of breeding pelicans to re-establish historic pelican nesting colonies.”
The Great Salt Lake’s water levels also play an important role for the pelicans and their nesting colonies on both Hat and Gunnison islands.
“Unfortunately, both Hat Island and Gunnison Island are still accessible to land-based disturbance, even though lake levels are currently rising,” Neill said. “The threat of nesting colony abandonment will continue to persist as long as the islands aren’t surrounded by water. Another factor is the amount of water in the two nearby freshwater bays: Bear River Bay and Farmington Bay. These two locations are where most of the nesting pelicans find food and water. When we have good runoff years, there are a lot more fish available in these areas, due to the increase in water and foraging habitat for pelicans.”
In addition to monitoring the populations of the pelicans that use the islands, the DWR also tracks their migration through periodic efforts of placing transmitters and bands on the birds. The pelicans typically stay at the Great Salt Lake from April to September and then migrate south for the winter. The pelicans often migrate between Texas and California, but have also been known to migrate as far as southern Mexico.
Learn more about the pelican banding and tracking efforts by visiting the DWR website and listening to the DWR Wild podcast.
