Chaetura vauxi
Silhouette: Aviceda (vectorized by T. Michael Keesey) · PhyloPic
In 3 days ~30% in a week ~50%
Vaux's swift (Chaetura vauxi) is a small swift native to North America, Central America, and northern South America. It was named for the American scientist William Sansom Vaux. This is a small swift, even compared to other Chaetura species, at 10.7 to 11.2 cm (4.2 to 4.4 in) long and weighing 18 g (0.63 oz). The northern populations are slightly larger at 11.5 cm (4.5 in), probably according to the Bergmann's Rule and/or migration requirements. It has a cigar-shaped body, crescentic wings and a short bluntly squared-off tail. The head, upperparts and wings are dusky black, and the underparts, rump and tail coverts are greyish brown. The throat is paler grey, becoming whitish in northern birds. The sexes are similar, but juveniles have dusky bases to the throat feathers.
Vaux's swift breeds in highlands from southern Alaska to central California and from southern Mexico, the northern Yucatán Peninsula, to eastern Panama and northern Venezuela. The United States' populations are migratory, wintering from central Mexico south through the Central American breeding range. The resident breeding birds in the southern part of the range are sometimes... Wikipedia →
| # | City | Country | Daily sighting probability |
|---|---|---|---|
| 1 | San Salvador | 🇸🇻 El Salvador | |
| 2 | Guatemala City | 🇬🇹 Guatemala | |
| 3 | Portland | 🇺🇸 United States | |
| 4 | San José | 🇨🇷 Costa Rica | |
| 5 | Mexico City | 🇲🇽 México | |
| 6 | Managua | 🇳🇮 Nicaragua | |
| 7 | San Pedro Sula | 🇭🇳 Honduras | |
| 8 | Seattle | 🇺🇸 United States | |
| 9 | Vancouver | 🇨🇦 Canada | |
| 10 | San Francisco | 🇺🇸 United States |
With luck
About 10% of wildlife watchers report a Vaux's Swift sighting in Mexico City on a given day, based on 1,245 verified sightings from GBIF citizen-science data. It is the 73rd most-seen of the 332 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.
February–March and October
In those months about 20% of wildlife watchers report a Vaux's Swift in Mexico City on a given day, against under 5% in June to August, the lowest months. Those are among Mexico City's driest months, with about 30 mm of rain a month against 150 mm in July.
Between 6 and 9 pm
Across all the parks we cover, that three-hour window holds the most Vaux's Swift sightings with a recorded time, and about 7 in 10 of them come between 6 am and 6 pm: it is most active around dawn and dusk.
5th of 19
Of the 19 cities where we can rate Vaux's Swift sightings, Mexico City ranks 5th at about 10%. The best odds are in San Salvador (El Salvador, about 30%), Guatemala City (Guatemala, about 20%) and Portland (United States, about 20%).
GBIF citizen-science records
It is estimated from how often the Vaux's Swift is recorded against all the birds logged in Mexico City (1,245 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.
