Spizelloides arborea
Silhouette: Ferran Sayol · PhyloPic
In 3 days ~10% in a week ~30%
The American tree sparrow (Spizelloides arborea), also known as the winter sparrow, is a medium-sized New World sparrow. It breeds in Alaska and Northern Canada and winters in Southern Canada and the Contiguous United States. It is the only member of the genus Spizelloides.
First described in 1810 by Alexander Wilson, it was included by John James Audubon in the first edition of The Birds of America under the name Canada bunting. The American tree sparrow was originally placed in the genus Spizella. In 2014, it was moved to its own monotypic genus, Spizelloides, based on polyphyly in Spizella and multilocus molecular evidence suggesting the species was strongly divergent from other extant genera.
The bird's measurements are as follows: Length: 5.5 in (14 cm) Weight: 0.5–1.0 oz (13–28 g) Wingspan: 9.4 in (24 cm) Adults have a rusty cap and grey underparts with a small dark spot on the breast. They have a rusty back with lighter stripes, brown wings with white bars and a slim tail. Their face is grey with a rusty line through the eye. Their flanks are splashed with light brown. They are similar in appearance to the chipping sparrow. Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Denali National Park | 🇺🇸 United States | |
| 2 | Kluane National Park | 🇨🇦 Canada | |
| 3 | Wood Buffalo National Park | 🇨🇦 Canada | |
| 4 | Katmai National Park | 🇺🇸 United States | |
| 5 | Point Pelee National Park | 🇨🇦 Canada | |
| 6 | Riding Mountain National Park | 🇨🇦 Canada | |
| 7 | Voyageurs National Park | 🇺🇸 United States | |
| 8 | Elk Island National Park | 🇨🇦 Canada | |
| 9 | Banff National Park | 🇨🇦 Canada | |
| 10 | Wrangell-St. Elias National Park | 🇺🇸 United States | |
| 11 | Acadia National Park | 🇺🇸 United States | |
| 12 | Great Bear Rainforest | 🇨🇦 Canada | |
| 13 | Rocky Mountain National Park | 🇺🇸 United States |
| # | City | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Chicago | 🇺🇸 United States | |
| 2 | Montreal | 🇨🇦 Canada | |
| 3 | Toronto | 🇨🇦 Canada | |
| 4 | Minneapolis [Saint Paul] | 🇺🇸 United States | |
| 5 | Denver | 🇺🇸 United States | |
| 6 | Detroit | 🇺🇸 United States | |
| 7 | Boston | 🇺🇸 United States | |
| 8 | Edmonton | 🇨🇦 Canada | |
| 9 | Calgary | 🇨🇦 Canada | |
| 10 | Philadelphia | 🇺🇸 United States |
| # | Zoo / Centre | Country | |
|---|---|---|---|
| 1 | Columbus Zoo and Aquarium | 🇺🇸 United States |
Rare
Under 5% of wildlife watchers report an American Tree Sparrow sighting in Denver on a given day, based on 2,541 verified sightings from GBIF citizen-science data. It is the 80th most-seen of the 299 birds we can rate there. Over three days the chance rises to about 10%, and over a week to about 30%, if each day is a fresh chance.
November to March
In those months about 10% of wildlife watchers report an American Tree Sparrow in Denver on a given day, against under 5% in April to October, the lowest months. Those are among Denver's driest months, with about 20 mm of rain a month against 60 mm in July.
Between 11 am and 2 pm
Across all the parks we cover, that three-hour window holds the most American Tree Sparrow sightings with a recorded time, and about 8 in 10 of them come between 6 am and 6 pm: it is a daytime animal.
5th of 18
Of the 18 cities where we can rate American Tree Sparrow sightings, Denver ranks 5th at under 5%. The best odds are in Chicago (United States, about 10%), Montreal (Canada, about 10%) and Toronto (Canada, about 10%).
Same family: Passerellidae
The closest relatives of the American Tree Sparrow that you can see in Denver (family Passerellidae, New World Sparrows) are Song Sparrow (about 40%), Spotted Towhee (about 40%) and Dark-eyed Junco (about 20%), with each one's daily chance of a sighting.
GBIF citizen-science records
It is estimated from how often the American Tree Sparrow is recorded against all the birds logged in Denver (2,541 verified sightings), 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.
