Pooecetes gramineus
Silhouette: L. Shyamal · PhyloPic
In 3 days ~30% in a week ~50%
The vesper sparrow (Pooecetes gramineus) is a medium-sized New World sparrow. The only member of the genus Pooecetes, it is a pale sparrow with brown streaks that breeds across the grasslands of northern North America. It migrates to winter in the southern United States and Mexico.
The vesper sparrow was formally described in 1789 by the German naturalist Johann Friedrich Gmelin in his revised and expanded edition of Carl Linnaeus's Systema Naturae. He placed it with the finches in the genus Fringilla and coined the binomial name Fringilla graminea. He gave the locality as New York. Gmelin based his own description on those for the "grass finch" that had been described by John Latham in 1783 and by Thomas Pennant in 1785. The vesper sparrow is now the only species placed in the genus Pooecetes that was introduced in 1858 by the American naturalist Spencer Baird. The genus name combines the Ancient Greek ποα (poa) meaning "grass" with οικητης (oikētēs) meaning "dweller". The specific epithet gramineus is Latin meaning "grassy" or "grass-like".
Three subspecies are recognised. Wikipedia →
| # | City | Country | Daily sighting probability |
|---|---|---|---|
| 1 | León | 🇲🇽 México | |
| 2 | Denver | 🇺🇸 United States | |
| 3 | San Antonio | 🇺🇸 United States | |
| 4 | Austin | 🇺🇸 United States | |
| 5 | Salt Lake City | 🇺🇸 United States | |
| 6 | Mexico City | 🇲🇽 México | |
| 7 | Monterrey | 🇲🇽 México | |
| 8 | Mesa | 🇺🇸 United States | |
| 9 | Phoenix | 🇺🇸 United States | |
| 10 | Guadalajara | 🇲🇽 México |
With luck
About 10% of wildlife watchers report a Vesper Sparrow sighting in Rocky Mountain National Park on a given day, based on 800 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 57th most-seen of the 223 birds we can rate there. Over three days the chance rises to about 30%, and over a week to about 50%, if each day is a fresh chance.
July
In that month about 20% of wildlife watchers report a Vesper Sparrow in Rocky Mountain National Park on a given day, against under 5% in October to March, the lowest months. That is one of Rocky Mountain National Park's wettest months, with about 95 mm of rain against 40 mm in September.
Between 9 am and noon
Across all the parks we cover, that three-hour window holds the most Vesper Sparrow sightings with a recorded time, and about 9 in 10 of them come between 6 am and 6 pm: it is a daytime animal.
4th of 25
Of the 25 parks where we can rate Vesper Sparrow sightings, Rocky Mountain National Park ranks 4th at about 10%. The best odds are in Yellowstone National Park (United States, about 20%), Big Bend National Park (United States, about 10%) and Grand Teton National Park (United States, about 10%).
Same family: Passerellidae
The closest relatives of the Vesper Sparrow that you can see in Rocky Mountain National Park (family Passerellidae, New World Sparrows) are Dark-eyed Junco (about 60%), White-crowned Sparrow (about 30%) and Lincoln's Sparrow (about 30%), with each one's daily chance of a sighting.
GBIF citizen-science records
It is estimated from how often the Vesper Sparrow is recorded against all the birds logged in Rocky Mountain National Park (800 verified sightings from 2019 to 2026), calibrated against known sighting rates. Figures are rounded to the nearest 10% because citizen-science data supports honest approximations, not decimals, and months with records from fewer than five people show "—". How it works.
