Libellula vibrans
In 3 days ~10% in a week ~30%
The great blue skimmer (Libellula vibrans) is a dragonfly of the skimmer family. With a total length of 50 to 63 millimetres (2.0 to 2.5 in), it is one of the largest skimmers. The immature forms of the skimmer are brown in color and mature forms are blue-hued. This species is found near lakes, ponds, and slow streams in the eastern United States and rarely in southern Ontario.
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| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Congaree National Park | 🇺🇸 United States | |
| 2 | Merritt Island National Wildlife Refuge | 🇺🇸 United States | |
| 3 | Great Smoky Mountains National Park | 🇺🇸 United States |
| # | City | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Washington | 🇺🇸 United States | |
| 2 | Houston | 🇺🇸 United States | |
| 3 | New York City | 🇺🇸 United States | |
| 4 | Austin | 🇺🇸 United States | |
| 5 | Baltimore | 🇺🇸 United States | |
| 6 | Dallas | 🇺🇸 United States | |
| 7 | Philadelphia | 🇺🇸 United States | |
| 8 | Chicago | 🇺🇸 United States | |
| 9 | Orlando | 🇺🇸 United States | |
| 10 | Miami | 🇺🇸 United States |
Rare
Under 5% of wildlife watchers report a Great Blue Skimmer sighting in Philadelphia on a given day, based on 22 verified sightings from GBIF citizen-science data. It is the 245th most-seen of the 632 insects 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.
May–June and August–September
In those months about 10% of wildlife watchers report a Great Blue Skimmer in Philadelphia on a given day, against under 5% in July and October–April, the lowest months.
Between 10 am and 1 pm
Across all the parks we cover, that three-hour window holds the most Great Blue Skimmer sightings with a recorded time, and nearly all of them come between 6 am and 6 pm: it is a daytime animal.
7th of 10
Of the 10 cities where we can rate Great Blue Skimmer sightings, Philadelphia ranks 7th at under 5%. The best odds are in Washington (United States, about 10%), Houston (United States, about 10%) and New York City (United States, about 10%).
GBIF citizen-science records
It is estimated from how often the Great Blue Skimmer is recorded against all the insects logged in Philadelphia (22 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.
