A Song for July 12

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In 1981 I took a summer off from my long-time post as resident naturalist at Cottonwood Gulch and scoured the Zuni Mountains for breeding birds. It wasn't a random sample, it was a targeted search in the most unusual habitats for the least expected species. I went to the highest, wettest spots and the lowest, driest ones, noting the birds I heard and saw, recording a few, and incidentally taking notes on plant distribution. As it turned out, I collected a good many "range extensions" for plant species, because this range was even less explored by botanists than by zoologists. In the process a found a Hammond's Flycatcher nest that proved this northerly species was nesting farther south than previously known, and found the first evidence of breeding in the Zuni Mountains for Tree Swallow, Olive-sided Flycatcher, Spotted Sandpiper, and several others.

I don't know if this whip-poor-will was the first ever heard in the Zunis by someone who would make a record of it, but I am confident it is the first sound recording of one. That is why I am presenting such a faint and low-quality recording here. This is documentation. It is glorious that eBird provides a platform for documenting bird occurrences that is accessible by all. That's a big step forward from the only form of documentation being a dried skin in a locked cabinet in a museum. Of course the printed-on-paper range maps still don't include the Zuni Mountains in the range of this species, but eBird will show you that the species has been reported there several times in this decade by dependable observers. Depending on your purposes, you can believe them or not.

In 1981 this bird was a Whip-poor-will, but today we have a choice to make. The erstwhile Whip-poor-will has been split into the Eastern Whip-poor-will, which summers in the northeastern U.S. and southeastern Canada, and the Mexican Whip-poor-will, which summers in the temperate highlands from Nicaragua to the southwestern U.S. We don't want to assume that this bird is the latter species just because it was found close to the known range of the species. Sometimes a bad rcording is good enough. We can clearly see that some of the whip notes have jagged traces. That is all we need to identify this bird as Mexican. It gives the sound its characteristic burry quality.

The whip-poor-will (both species) has an incongruous breeding range: eastern North America and the Middle American temperate highlands. The range of the Eastern Bluebird is very similar. In both cases there is a sizable gap between the two populations. At one point these two populations were one. Where was it found, and how was it sundered in this way? Better yet, what will happen next? I predict both western forms will continue moving north. The Western Bluebird, though, may stymie the Eastern's advance. They are very similar in size and shape, and probably ecology. Which would "competitively exclude" the other is anyone's guess. The Common Poorwill, on the other hand, may not be much of an obstacle for the whip. It is smaller, and has already ceded the highlands where the ranges of the two overlap. The Mexican Whip-poor-will may march all the way to Canada, displacing the poorwill from the upper elevation forests, but leaving to it the deserts, foothills, and lower slopes of the mountains. Time will tell.

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Nathan D. Pieplow. 2017. Peterson Field Guide to Bird Sounds of Eastern North America. Houghton Mifflin Harcourt.
Nathan D. Pieplow. 2019. Peterson Field Guide to Bird Sounds of Western North America. Houghton Mifflin Harcourt.
Donald Kroodsma. 2005. The Singing Life of Birds. Houghton Mifflin.