Rare Birds Are Common!

On my Recent trip to New England, the rarest bird was a common gull (Larus canus), a diminutive white headed larid from Europe that was staked out with a group of our familiar Ring-billed Gulls (L. delawarensis) in a northeast Connecticut shopping center parking lot. Encountering seagulls in a paved parking lot away from the sea coast is mundane, i.e a common phenomenon. Both Ring-billed Gull and Common Gull are well adapted to habitats dominated by humans (such as shopping centers and parking lots). These birds are not picky eaters. They will eat garbage items generated by humans (such as leftover food from household meals and restaurant kitchens) as well as fish and crustaceans found in ponds, lakes, bays, and oceans. They are also happy to accept food donations and will gladly devour any morsel of food offered by humans that pass nearby to their hangouts. In certain places, gulls have become quite confiding and will attempt to steal food from picnic baskets or even from your hands if you are not paying attention. French fries seem to be highly valued by Ring-billed Gulls as food items. For this reason, they often hang out near fast food venues. I suspect this to be true for gulls not only in North America but also in the other hemispheres. In the case of Common Gull, I have observed them to be abundant in city parks in Iceland and Germany. Outside cities, they are numerous in agricultural settings where huge numbers of them will forage in recently tilled fields, hoping to find leftover crops from recent harvesting operations or worms and grubs that are exposed by tractors turning the soil. The same is true for Ring-billed Gulls in the farm belts of the USA. As human populations grow, the numbers of human-adapted gull species are also growing. A small portion of these explore new migration routes, or accidentally cross the oceans during storms or assisted by ships. It is a numbers game. So a rare sighting of a misplaced species in a new location has become commonplace. Consider also that there are many abundant species from other continents that are eligible to become vagrants to our shores (and inland areas as well), and the increased number of skilled birders watching for these misfits, the probability that any one birder may see these oddities has increased. My trip to New England seems to confirm this situation. In just under a week, I saw Barnacle Goose, Black-headed Gull, Common Gull and Tufted Duck, all vagrants from northwestern Europe. 

It is ironic that the “common name” for Larus canus is “Common Gull” given its rarity in the USA, where it is decidedly not common. Of course, this is due to a confusing aspect of the English language. There are at least three different meanings of the word “common”:

1. Abundant; occurs at high frequency or present in high density
2. Widespread 
3. Mundane; vernacular 

The Common Gull was named “common” not because of its abundance but rather because it was considered to be widespread. It bred and wintered across the Old World from the Atlantic coast to the Pacific coast. In the New World, however, it is fair to say “Common Gulls are rare”. I should point out the Short-billed Gull (L. brachyrhynchos), a common species of gull that breeds in the northwest of the North American continent, was long considered to be a subspecies.of Common Gull, until 2021 I think. The North American Checklist Committee of the American Ornithological Society recently upgraded its taxonomical status to full species level. In the field, they are almost inseparable.

Another species that is rare in North America is the Common Crane (Grus grus) which also is found across the Eurasian continent, like the Common Gull. For several decades, one or two individuals of this iconic Old World species have been appearing annually in the USA during winter, hanging out with and migrating with flocks of Sandhill Crane (G. canadensis). Some of the Sandhills migrate northwest across the Bering Strait to breed in eastern Siberia. There, the range of the two crane species overlaps. Apparently, some of the Common Cranes of eastern Siberia migrated southeast with Sandhills rather than southwest with their own kind, and the phenomenon has continued for years. On Thursday, March 17, 2023, a report surfaced of a Common Crane among hundreds of northbound Sandhill Cranes that had settled to roost along the North Platte River at Lewellen in Garden County, Nebraska. I received this news from my friend David Wade about noon on March 18. Lewellen is just over 3 hrs from Fort Collins. I immediately started texting friends who might want to go on a wild crane chase. One of these responded favorably, and by 3 PM Cole Wild and I were racing across the eastern plains of Colorado hoping to reach Lewellen before sunset. We also hoped that the roosting cranes were within view of a public road. We couldn’t count on local intelligence from birders because this part of western Nebraska is largely unpopulated. This under-birded part of Nebraska is located about 20 miles north of the northeast corner of Colorado.

We arrived about an hour before dark and quickly found a large flock of foraging cranes in wheat stubble near the river. We carefully studied each bird, searching for the black neck that is unique to the Common Crane. Not having any luck we arrived at the highway bridge over the river and watched as dozens of crane flocks, each with hundreds of birds, passed high overhead from all directions settling in to roost for the night in the shallow river.  Finding this vagrant Common Crane was going to be more difficult than we realized. We pondered our strategy as we drove to the nearest motel 30 miles away.

The following morning (Sunday, March 19, 2023), we began our search at sunrise from the bridge. There were about a thousand cranes still in the river too distant to study. So, we began driving country roads looking for foraging flocks. Several hours passed and we had perused several thousand birds with no luck. Then at 10:30 AM, we noticed an exodus of cranes from the corn field and wheat fields, returning towards the river. We followed them and found a massive flock of about 10,000 cranes packed together in a grassy field adjacent to the river. We had about an hour before we had to return to our families in Colorado.  We searched and searched and searched every individual crane, using spotting scopes. At 11:40 AM, Cole announced “Got it!”  Sure enough, he had spotted the needle in the haystack. And just in time for us to meet our family obligations back in Colorado. To see photos of the Common Crane (year bird 486), you can check out my eBird checklist here: https://ebird.org/checklist/S131299323.

The Common Crane and the Common Gull are two examples of “common” birds that are rare. But one concept that my Big Year experience has reconfirmed for me is that the opposite is equally true: Rare birds are common. Everywhere I have traveled for my Big Year, I have encountered species classified as rare in eBird. Many of my checklists include a rare species or two. Sometimes even more. My friend John Vanderpoel observed about 40 vagrants during his successful Big Year effort in 2011. These were mega-rarities, birds classified by the American Birding Association (ABA) as Codes 3, 4 and 5. At the time of this posting (March 31, 2023), I have 13 such rarities on my list, on track for about 40 also!

Of course not all rare birds in eBird are ABA mega-rarities. eBird considers seasonality and geography such that a species may be considered rare one week and common the next week, or rare in one county and common in the next. Oddly, I’ve noticed that a relatively small number of birders ever report rarities. I believe this is because the concept of rarity implies that a species does not belong and therefore encountering one does not compute in the brains of many birders. To find a rarity one must keep an open mind to the possibility of its occurrence. It’s actually just a numbers game. I think of it this way. A frequency of 1 per thousand or fewer is what I would consider rare. So, in a flock of a thousand geese, I expect to find a rare goose.  A mudflat crawling with a thousand shorebirds should host a rare one amongst them. In my home county of Larimer in north central Colorado, we regularly expect to find about 300 species each year. That leaves over 600 species from the ABA Checklist for the USA to occur as a rarity. So, while it would be unexpected to observe any one of these, I would expect to find some of these each year just because of the number of birds that pass through annually. 

I suspect many timid birders are hesitant to claim a rarity observation because of the interpretation of eBird’s requirement for comments as questioning their integrity or their birding skills. But my message to all birders is this: Expect to find rare birds as “rare birds are common.” And if all birders reported the rarities they observe, we would find that they are even more common than we thought.