Brachydiplax chalybea
In 3 days ~70% in a week >90%
Brachydiplax chalybea is a species of dragonfly in the family Libellulidae. It is known by the common names yellow-patched lieutenant, rufous-backed marsh hawk, and blue dasher. It is native to much of eastern Asia, from India to Japan to Indonesia.
The male of the species is 33 to 35 millimeters long and has a hindwing 24 to 27 millimeters long. It is powder blue with light brown sides and a dark tip to the abdomen. Wings are hyaline, with tinted burnt-brown base, fading to amber. The female is brownish yellow in color with darker markings along the dorsal abdomen. Its wings lack the yellow tinge. This species can be easily distinguished from other species in this genus by its larger size, characteristic colour of the thorax, and bases of wings.
This species is found in many types of wet habitat, including brackish and disturbed waters. The males are seen more often, due to their territorial behavior. Females oviposit by "flicking" an egg mass out of the water into rocks and vegetation nearby.
Brachydiplax chalybea of Borneo Island Data related to Brachydiplax chalybea at Wikispecies Media related to Brachydiplax... Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Sundarbans National Park | 🇮🇳 India | |
| 2 | Sepilok | 🇲🇾 Malaysia | |
| 3 | Kinabatangan Wildlife Sanctuary | 🇲🇾 Malaysia | |
| 4 | Khao Sok National Park | 🇹🇭 Thailand | |
| 5 | Kaeng Krachan National Park | 🇹🇭 Thailand |
| # | City | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Dhaka | 🇧🇩 Bangladesh | |
| 2 | Kochi | 🇮🇳 India | |
| 3 | Thrissur | 🇮🇳 India | |
| 4 | Ponnani | 🇮🇳 India | |
| 5 | Kolkata | 🇮🇳 India | |
| 6 | Kozhikode | 🇮🇳 India | |
| 7 | Bangkok | 🇹🇭 Thailand | |
| 8 | Yogyakarta | 🇮🇩 Indonesia | |
| 9 | Thiruvananthapuram | 🇮🇳 India | |
| 10 | Johor Bahru | 🇲🇾 Malaysia |
Likely
About 40% of wildlife watchers report an Oriental Blue Dasher sighting in Sundarbans National Park on a given day, based on 8 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 5th most-seen of the 15 insects we can rate there. Over three days the chance rises to about 70%, and over a week to over 90%, if each day is a fresh chance.
April
In that month about 70% of wildlife watchers report an Oriental Blue Dasher in Sundarbans National Park on a given day, against about 10% in January–March, July–August and November, the lowest months. That is one of Sundarbans National Park's driest months, with about 55 mm of rain against 480 mm in July. June has too few records to rate.
Between 2 and 5 pm
Across all the parks we cover, that three-hour window holds the most Oriental Blue Dasher sightings with a recorded time, and about 8 in 10 of them come between 6 am and 6 pm: it is a daytime animal.
Yes
Of the 5 parks where we can rate Oriental Blue Dasher sightings, Sundarbans National Park has the highest daily chance: about 40%. Next come Sepilok (Malaysia, about 20%) and Kinabatangan Wildlife Sanctuary (Malaysia, about 20%).
Same family: Libellulidae
The closest relatives of the Oriental Blue Dasher that you can see in Sundarbans National Park (family Libellulidae, Skimmers) are Scarlet Skimmer (about 40%), Pied Paddy Skimmer (about 40%) and Ditch Jewel (about 30%), with each one's daily chance of a sighting.
GBIF citizen-science records
It is estimated from how often the Oriental Blue Dasher is recorded against all the insects logged in Sundarbans National Park (8 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.
