Tachycineta thalassina
Silhouette: Andy Wilson · PhyloPic
In 3 days ~20% in a week ~30%
The violet-green swallow (Tachycineta thalassina) is a small North American passerine bird in the swallow family. These aerial insectivores are distributed along the west coast from Alaska to Mexico, extending as far east as Montana and Texas. With an appearance very similar to the tree swallow, these individuals can be identified by the white rump side-patches that appear to separate their green back and purple tail. Violet-green swallows are secondary cavity nesters, found in a number of habitats including deciduous and coniferous forest. In addition to nesting in tree holes within these habitats, they are also widely observed nesting in the cracks of large cliffs.
The distinct body form of swallows distinguishes them from other passerine birds. Their long pointed wings and slim, streamlined body evolved to catch insects while in flight; the violet-green swallow is no exception. With an average body length of 12–13 cm (4.7–5.1 in), the violet-green swallow is slightly shorter and appears more compact in flight compared to some other members of the genus Tachycineta. The violet-green swallow most closely resembles the tree swallow T. bicolor, but can be distinguished... Wikipedia →
| # | City | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Toluca | 🇲🇽 México | |
| 2 | Portland | 🇺🇸 United States | |
| 3 | Seattle | 🇺🇸 United States | |
| 4 | San Francisco | 🇺🇸 United States | |
| 5 | Vancouver | 🇨🇦 Canada | |
| 6 | Anchorage | 🇺🇸 United States | |
| 7 | Denver | 🇺🇸 United States | |
| 8 | Calgary | 🇨🇦 Canada | |
| 9 | Mexico City | 🇲🇽 México | |
| 10 | Mesa | 🇺🇸 United States |
With luck
About 10% of wildlife watchers report a Violet-green Swallow sighting in Denver on a given day, based on 2,910 verified sightings from GBIF citizen-science data. It is the 74th most-seen of the 299 birds we can rate there. Over three days the chance rises to about 20%, and over a week to about 30%, if each day is a fresh chance.
May
In that month about 20% of wildlife watchers report a Violet-green Swallow in Denver on a given day, against under 5% in August to March, the lowest months. That is one of Denver's wettest months, with about 60 mm of rain against 15 mm in January.
Between 8 and 11 am
Across all the parks we cover, that three-hour window holds the most Violet-green Swallow sightings with a recorded time, and about 9 in 10 of them come between 6 am and 6 pm: it is a daytime animal.
7th of 17
Of the 17 cities where we can rate Violet-green Swallow sightings, Denver ranks 7th at about 10%. The best odds are in Toluca (México, about 40%), Portland (United States, about 10%) and Seattle (United States, about 10%).
GBIF citizen-science records
It is estimated from how often the Violet-green Swallow is recorded against all the birds logged in Denver (2,910 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.
