Novembirding: Documenting Vagrancy in a Changing World

November is a season for rarities. This time of year is celebrated as The Weird Month, when wayward vagrants wander to distant lands where they delight and bewilder expectant birders. Rare birds have been at the forefront of my mind more than usual this year as a result of my newfound duties on the New York State Avian Records Committee. In the process of crafting a special NYSARC report on recent additions to the official state checklist, I pored over innumerable reports of spectacular sightings from the past few years. The exercise got me thinking about vagrancy in a broader scope, from the complex suite of driving forces behind the phenomenon itself to the dramatic sagas of far-flung rarities that capture the collective imaginations of the birders around the world.

Situated at the tail end of post-breeding migration and just before winter’s worst sets in, November frequently sees a diverse array of vagrant birds ranging from inexperienced juveniles that took a wrong turn to battered storm waifs blown far off-course. I have never had a November go by without some kind of unexpected rarity turning up, and some seasons have delivered truly spectacular surprises that count among the most memorable highlights of my entire birding career. Standouts over the years include the famously ill-fated Long Island Corn Crake of 2017, a Common Cuckoo outside Providence in 2020, New York’s first Limpkin up by Niagara Falls in 2022, and of course the Black-chinned Hummingbird that made birding history at Randall’s Island in 2023. Countless birders across the continent have documented their own laundry lists of November treasures, which has understandably earned the month a prestigious position in the eyes of the community at large.

In keeping with established tradition, November 2024 has delivered more than its share of excitement on the vagrancy front. Chief among this year’s prizes was a dazzling male Bullock’s Oriole, a new bird for my New York list, which required a return trip to Stillwell Woods Park after it gave me the slip on my first attempt. A marvelously accommodating Sage Thrasher at Robert Moses State Park was only my second sighting in the Empire State, and I was pleased to connect with a Western Kingbird at Jones Beach for the first time in several years. This hat trick of western rarities undoubtedly helped to make for a particularly memorable month, and there were plenty of other patch birding and yard listing treats to be enjoyed over the course of the intervening weeks as well.

With my busy work schedule restricting my opportunities for birding expeditions, I have hardly scratched the surface of the available rarities on offer in the surrounding region this season. Other recent vagrants of note that I have been unable to chase include a Western Flycatcher in Westchester, a Lazuli Bunting in Dutchess County, a MacGillivray’s Warbler on Staten Island, and an expansive Cave Swallow influx that brought birds to the Great Lakes, the Finger Lakes, the Hudson Valley, and the South Shore of Long Island. Fortunately for me, all of these species are already represented on my prized New York list, which perhaps speaks to the inescapable diminishing returns of racking up a lifetime home state tally in excess of 400. Nevertheless, these records serve to highlight the remarkable birding bounty of the late fall season, and there are undoubtedly more surprises still awaiting discovery in the final stretch of 2024.

The Cave Swallows, in particular, represent a fascinating case study in vagrancy events that occur on a grander temporal and geographic scale. Although these aerial insectivores are native to warmer climes in the Southwest and the Caribbean, they appear with some regularity in the Northeast during late fall, sometimes in impressive numbers. Over the years, hobbyist birders and professional ornithologists have collaborated to study this pattern of occurrence, building a collective understanding that now allows us to predict these arrivals with impressive accuracy. Prolonged periods of southwesterly flow at this time of year ferry Cave Swallows far to the northeast of their typical range, where they are subsequently driven to the coast by cold fronts sweeping in from the northwest. This year’s incursion was prognosticated long before the first sightings hit the rare bird alert airwaves, and within no time there were dozens of swallows documented along the barrier beaches and lakeshores from the Maritimes to the Mid-Atlantic.

November 2024 has proven to be a particularly impressive month for these kinds of widespread, weather-driven avian happenings. The past week has seen exciting reports of Palearctic waterbirds like Northern Lapwing, Common Shelduck, and Eurasian Curlew turning up in eastern Canada, apparently carried across the ocean by strong, sustained easterlies which may yet deliver more bombshell birds. The islands of western Alaska are always productive during the fall, with highlights of this season including a pair of Eurasian Sparrowhawks and good numbers of both Song Thrushes and Eurasian Bullfinches. Perhaps most shocking of all is a developing spate of Short-tailed Shearwater reports from mind-boggling locations like interior Saskatchewan and the Great Lakes region. It appears that this Pacific species has been prospecting further east into the increasingly open waters of Arctic Canada, only to be iced out by the delayed autumn freeze and driven south by fierce winds. These inland records were wholly unprecedented until just last November, when New York’s first Short-tail was spotted along the shore of Lake Ontario, which hints that these stunning vagrants could represent the beginning of a new, and potentially predictable, seasonal pattern.

Curious minds cannot help but to ask deeper questions about the hows and whys of vagrancy, especially in terms of what it may reveal about the world around us. What can we hope to learn from a restless sea-eagle roaming the wrong hemisphere or a storm-tossed flush of flamingos scattering across the nation? We birders tend to get invested in the narratives of high-profile vagrants, and closer examinations of the backstories behind these journeys often unearth surprising insights about the ever-shifting state of the global environment. Even a sighting as gobsmackingly absurd as a tropical booby soaring over a metropolitan apartment starts to make a bit more sense when you begin looking into the broader context in which the record occurred. 

A number of my friends in the world of academia have studied vagrancy extensively, endeavoring to understand its mechanisms and functions, as well as their implications for avian ecology and evolution. While many vagrants, regrettably but unsurprisingly, do not survive their unplanned odysseys, those that do may establish far-flung toehold populations or even speciate into new forms over time, as illustrated by the evolutionary history of various island birds like the Hawaiian honeycreepers. In this regard, vagrancy serves as a valuable insurance policy that augments the adaptive flexibility, and thus the odds of long-term survival, for species that undertake such risky voyages. Potential causes of vagrancy are evidently as varied as the vagrants themselves, ranging from shifts in local weather patterns to geomagnetic storms that impact the whole of the planet. Though some vagrants are indeed whisked astray by strong winds, this oversimplification is perhaps leaned on a bit too heavily in many cases where the actual inciting factors are far more nuanced and arcane. Reverse migration, overshoots, and population booms are just a handful of examples of forces that can drive birds to disperse beyond their typical range. Minds far smarter than mine have grappled with the complexities of this phenomenon for decades, but those of us who work outside the realms of universities and laboratories still have an important role to play in unraveling the secrets of bird movements.

The birding world is more connected than ever, making us better equipped to document these happenings and attempt to wrap our heads around them. The resources available to beginners and the speed of communication with like-minded experts around the globe have changed our understanding of vagrancy forever. A stray international wanderer at a novice naturalist’s suburban feeder would likely remain an obscure, unresolved mystery in the era before omnipresent cameras and internet forums; nowadays such a bird gets identified promptly and makes headlines for the influx of cash it brings to the local community. The 2024 American Flamingo that furnished New York with its first accepted record was far from the first individual to appear in the state, but the previous half dozen sightings from last century were discounted out of hand as likely escapees due to our limited comprehension of movement potential in this species. Even new discoveries, however, often open the door for further questions. Take Limpkins, for example. After several consecutive years of birds surging northwards, claiming uncharted territory with steadily increasing volume and frequency, extralimital records slowed to a trickle in 2024. Was this a single off season for Hot Limpkin Summer, with the drought conditions that may have impelled the birds out of range somewhat ameliorated by increased rainfall in the southeast, or has the excitement peaked and ebbed for good? Only time will tell, and it will largely be birders and casual observers whose time tells the next chapter of the story.

We live in times of great uncertainty and dramatic change, both societal and environmental. Birds often serve as conspicuous bellwethers for shifts on the latter front, and instability on the former undeniably leads to ripple effects that are felt throughout the natural world. Anthropogenic forces like habitat fragmentation, large scale pollution, and introduction of invasive species all have repercussions for wildlife, and documentation of how bird populations respond to these factors is critically important. Vagrancy may provide some species with a fighting chance of keeping up with a rapidly changing climate, or even allow others to flourish in newly suitable habitat. Extralimital records of Yellow-headed Caracara popping up in the southern United States and around the Caribbean likely represent advance troops of the core population’s ongoing march through Central America, just as our own familiar garden birds like Northern Cardinal and Carolina Wren have continued to creep northwards in recent decades. Given the dizzying pace of our modifications to the planet, however, there are certain to be many more species that will struggle to adapt. Keeping close tabs on range expansions and contractions helps us to build a better understanding of how birds are coping, or failing to cope, as the environment transforms around them.

Perhaps even more important than the research value of birding is the personal, psychological benefit it brings to those who partake in the craft. The merits of “ornitherapy” are well documented, which is not to be taken lightly in this chaotic day and age. Birding helps to ground us, placing our finger firmly on the pulse of the planet, and even small-scale local observations can generate data that may help to drive positive developments in our communities. Knowledge is power, and improved environmental awareness profits us all. In a world where folks increasingly feel disconnected from nature and powerless to bring about significant change, the observation and documentation of birds is a tangible, meaningful activity that can provide both a private sense of achievement and valuable scientific discoveries. One of the best things about birding is that it can be whatever you make of it. Whether you view the pastime as a contemplative solo venture, a collaborative citizen science project, or anything in between, the thrill of unexpected visitors from faraway lands is a universal joy. While it is crucial to remember that each vagrant bird is a living, complex organism beyond the hit of dopamine that its appearance may provide, the acknowledgement of that reality does nothing to diminish the inherent worth of said avian-induced dopamine for those of us who are fortunate enough to observe them.

Personally, I have long felt that the act of birding helps me to better understand the world around me and my place in it, and rare birds certainly represent a major piece of that puzzle. My fascination with vagrancy has driven me to improve as both a naturalist and an educator, and the opportunity to serve on NYSARC and the eBird review team has amplified that drive even further. With the final curtain call of 2024 drawing ever closer, I can confidently state that this has been one of the most remarkable and productive years of my life to date. While I cannot say what the years to come may have in store, I can promise that I will be watching, documenting, and studying the comings and goings of birds for as long as I have breath in my lungs. There is always something new to learn from nature, if only we take the time to open our eyes and look around.