The Changing Seasons - Lesser Black-backed and Ring-billed Gulls

As part of what will likely be a lifelong effort, we are attempting to digitize historical reports of bird sightings from Newfoundland and Labrador. Ultimately, this means adding written reports to eBird whenever possible - providing a fully searchable and public database for these records. Naturally, there is great interest in records of rarities. However, just as interesting are the common species and the profound changes that birders have documented over the decades.

The written record of bird distribution is fairly comprehensive from the 1950s onwards. This series of articles will focus on notable changes over the past ~75 years that may not be obvious to the dedicated birder today. Certainly significant changes occurred prior to the 1950s but without a written report to review, those changes will remain a mystery.

Following is a breakdown of some of the most notable changes I have noted, including some theories to explain the changes. 

Note that this is the second in a series of blog posts on this topic.

The first post about goldfinches, redpolls, and song sparrows can be found here.

Lesser Black-backed Gull:

It might come as a surprise to some, but the first record of this species for Canada was in 1968 in Churchill, Manitoba at a time when the species was still considered very rare in North America. Newfoundland and Labrador's first record was in March 1972 at Quidi Vidi Lake. Nowadays, Lesser Black-backed Gulls (LBBG) are well-established in North America as a migrant and over-wintering species. Despite their abundance, there are no known breeding sites in North America. 

LBBG's underwent a range expansion in Northern Europe in the first half of the 20th century before undergoing a rapid transatlantic expansion [Ayyash 2024]. They have now been breeding in Greenland for several decades. The obvious explanation for their numbers in North America is that this breeding population migrates to and from North America, where it spends the winter. 

Peak Spring migration in NL occurs throughout April and early May with a significant corridor passing over the Gulf of St. Lawrence, including the West coast of Newfoundland towards Southern Labrador. I personally believe that the vast majority of North America's LBBGs use this corridor. I am not aware of any formal estimates on their numbers, but I suspect the number passing through our province is in the 10s of thousands per year. The current high count for the province was up to 98 in early June in Rocky Harbour (likely dominated by immatures at that time of year).

All nine Lesser Black-backed Gulls equipped with satellite transmitters in Pennsylvania ended up passing through our province.

See map and details here.

Gulls (including three adult LBBG's) migrating past Southern Labrador in early May 2022 - Vernon Buckle

There are now several records of hybrid Lesser Black-backed X Herring Gulls. No one really knows where these birds are coming from, but it is certainly conceivable that Lesser Black-backed Gulls are interbreeding with American Herring Gulls somewhere in Labrador. There may even be an undiscovered breeding population of LBBG's in the region!

Of note, Bruce Mactavish did document a LBBG apparently courting with a hybrid LBBG x AHGU in Happy Valley-Goose Bay in 2008:

Adult LBBG (darker gull at the back) in apparent courtship with a hybrid LBBG x AHGU in Happy Valley-Goose Bay, late May 2008 - Photo by Bruce Mactavish

Ring-billed Gull:

This species suffered major declines in the middle of the 20th century,  attributed to the use of DDT. After the substance was banned, they made a major rebound across the continent including Newfoundland and Labrador. 

In Birds of Newfoundland published in 1951, Peters and Burleigh state that Ring-billed Gulls are an uncommon summer resident on the island. In Birds of the Labrador Peninsula and Adjacent Area published in 1963, Todd writes that Ring-billed Gulls are a highly improbable breeding species in the Labrador region.

The first breeding record of Ring-billed Gulls for Gros Morne National Park occurred in 1986. 

Ring-billed Gulls were said to have gone from being a very uncommon migrant to a common migrant within less than 10 years in L'Anse-aux-Meadows leading up the mid 1980s. George Brinson, a long-term birdwatcher in Carmanville, reported that they became very common in his area in the early to mid 1980s. 

Nowadays, Ring-billed Gulls breed across the island of Newfoundland and on multiple islands around Lake Melville in Labrador. 

Although they often breed in conspicuous colonies, it is surprisingly difficult to confirm breeding locations using eBird data. Ring-billed Gulls are such a common species that most of us do not pay them much attention. To add to the challenge, they commute large distances to and from their breeding sites making breeding sites challenging to track down. For example, Ring-billed Gulls can be found around St. John's throughout the Summer without any difficulty. Yet, the closest breeding site that I am aware of is in Conception Bay South (22 km or more SSW of Quidi Vidi lake). 

Ring-billed Gulls breeding at a colony in Spaniard's Bay

Photo is courtesy Frank King

I can think of only 6-8 colonies of this species on the Avalon Peninsula. Surely there are more that are not recorded. eBird and NF breeding bird atlas are great spots to report bird colonies. Make sure to add the breeding evidence to your reports!

The colonies on the Avalon peninsula that we are aware of include:

• Spaniard's Bay
• Renews
• Trepassey harbour
• Cootes Pond
• O'Donnell's
• Island in Salmonier Arm (adjacent to New Bridge)
• Kelly's Island (just South of Bell's Island)
• Rosses Island (just off Dildo)

Two other possible locations include:

• Perlican Island (I'm not actually 100% sure that RBGU's breed here)
• Ferryland
• Island just South of Arnold's Cove

If you are aware of other breeding colonies around the Avalon peninsula, I would be interested to hear about them.

Anecdotally, some folks, particularly on the Northern Peninsula, have reported declines in Ring-billed Gulls in recent years. So it certainly is worthwhile to continue keeping a close eye on their breeding colonies and attempting to count them when you can. In fact, as of 2024 two breeding colonies on the Avalon were knocked off the list:

• Island off of Bellevue beach 
• Long Pond Harbour in CBS - apparently these birds moved to nearby Kelly's Island

What changes have you noticed in bird numbers and distributions in our province? Do you have any predictions on what might change in the next few decades?

The next article in this series will outline changes in waterfowl. 

If you have any feedback on this or any other blog posts, please do not hesitate to share. 

- Alvan