"Right now, it sounds great to know as little as possible. It makes me sad that we both know, and we’ve both seen how terribly hostile and unforgiving all of this can get. I shudder to think the entire world can be erased in the blink of an eye without so much as a warning."
― Nick Vossen
Behold! This is the Chequamegon-Nicolet National Forest — 1.5 million acres of Wisconsin's Northwoods. See that little yellow 'X' in the upper-left? Allegedly, that's where the last three pairs of Connecticut Warblers are nesting in Wisconsin. This is according a conservation biologist with the Wisconsin Department of Natural Resources:
"Connecticut Warblers have declined precipitously to the point where we now have only one known nesting site in the state, holding a mere three pairs as of last year. I'd beg the birding community to reconsider visiting this location. While they can be heard from a road and many birders are well behaved, some trespass on the private land holding the birds, others play recordings to lure them out, and all risk repeated disturbance that could impact nesting success and their perpetuity as a breeding species in the state. Even the well-intentioned can cause harm by eBirding their results without hiding their checklists and leading the less well-intentioned directly to the birds. Often this includes out-of-area visitors who have no idea of their plight."
Last year a concerned birder told me the following about this particular site:
"Those are the last 3 breeding CONW in the state, and they are being eBirded too often. I am afraid for them — I'm convinced that we're losing my favorite warbler. I found these years ago when the rest and I mean all the rest of their breeding habitat had been clear-cut. I told one wrong person and now its a zoo. I feel terribly guilty."
Context! According to Birds of North America:
"Classified globally as a species of Least Concern by BirdLife International owing to its large range and population size (1,800,000 individuals; see Population Status). Although the global population is believed to have declined by 0.8% annually from 1966–2019, the decline was not sufficiently rapid to approach the thresholds for Vulnerable by BirdLife International. The Connecticut Warbler received a G4 (Apparently Secure – low risk of extinction but cause for concern) Global status ranking from NatureServe. The Connecticut Warbler is currently considered a Group 2 - Mid-priority candidate for extinction by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC). Connecticut Warbler is on the Yellow Watch List of Partners in Flight owing to a combination of vulnerability scores: a high vulnerability score due to population decline and moderate vulnerability scores for population size and threats on the breeding and overwintering ranges."
Could Wisconsin's dearth of Connecticut Warblers be due to habitat fragmentation? The concerned birder certainly believes so, and apparently feels personally responsible for their demise in reporting the site to other birders.
So, here's a zoomed area of the 'X':
Again, from Birds of North American:
"Hallworth et al. found a strong correlation between population declines and habitat fragmentation on the breeding grounds. Habitat loss had a greater impact on eastern and southern populations breeding in jack pine (Pinus banksiana), tamarack (Larix laricina), and black spruce (Picea mariana) forests compared to northwestern populations that breed in upland aspen forests. Some of the leading causes of population decline in Minnesota are habitat loss and fragmentation. Loss of important jack pine forest has occurred in Wisconsin due to outbreaks of spruce budworm (Choristoneura fumiferana) and fire suppression."
Is this decline due to birders eBirding, habitat mismanagement, bad ecological circumstances, or a combination of all three? Or perhaps something else is going on we don't yet know about.
Here are eBird pins for 'X' area over the last decade, which excludes 2023:
Same concerned birder also told me:
"I could easily find 60 or more on a given day 20 years ago. If all of the known areas are checked and there are no birds, if all of their habitat has been clear-cut I can't imagine where they would be."
Sixty!? Even though the above map only goes back a decade, none of those pins show anything like that; the largest concentration around 4 or so individuals, most pins represent a mere single bird.
From WI DNR's website, here's a habitat suitability map for Connecticut Warbler:
Key: Natural communities that are associated with Connecticut Warbler. Only natural communities for which Connecticut Warbler is "high" (score=3) or "moderate" (score=2) associated are shown.
Things to ponder:
With all this abundant and available (albeit differentially fragmented) habitat, is the 'X' really the last CONW nesting site in Wisconsin? I've been told thorough searching has been done, but that's a substantial tract of land to check for a very secretive species. It should also be noted that the 'X' is not far from where the DNR conservation biologist lives; the concerned birder also lives in that area — what have they personally covered land-wise?
One wonders if climate change may be a factor — is the range shifting northward in response? Perhaps it's an inevitable consequence of warming temperatures that habitat is slowly changing and this species no longer choose to nest in northern Wisconsin. Do we fix that by asking birders to avoid certain areas?
My Conclusion:
Is the Connecticut Warbler threatened with extinction? No, it isn't. Might it be extirpated from Wisconsin? That's certainly a possibility, but I strongly suspect there are potentially far more nesting sites in the state that haven't been detected despite whatever search thoroughness has been done or alleged. In any case, birds don't respect borders — they just want appropriate habitat and this species is doing fine elsewhere ... for now. Does this affect me? No. Fortunately, I manage to find Canada-bound birds (apparently) during spring migration. Also, one wonders how much this is merely 'rules for thee, but not for me.'
Lastly, the concerned birder shouldn't feel too badly. It's very likely other birders would have found the site anyway with the same resultant crisis. It doesn't take super-powers to find them, but it does beg the question if this birder thinks they're so difficult to find, then maybe they really are and the northern half of the state is teeming with them. To that sentiment — and this will blow your mind — the CONW population in northern Wisconsin was estimated at 9,430 individuals in 2010 (Beaudry, F., A. M. Pidgeon, V. C. Radeloff, R. W. Howe, D. J. Mladenoff, and G. A. Bartelt). I doubt there are that many, but I would wager there are vastly more than just six individuals.