Wisconsin Odonata Survey

Back

Aeshna canadensis  Walker, 1908
Canada Darner


Aeshnidae, Darner Family

The mosaic darners of the genus Aeshna (aka blue darners) are large, strong-flying dragonflies with late-season flight periods. Most are similar to each other in size and general coloration, so in-hand examination is usually necessary to identify them. The most important distinguishing characteristics for this genus are the shapes and colors of the pale stripes on the sides of the thorax, especially the first or anterior stripes (here referred to as anterior thoracic side stripes [ATSS]), and the shapes of the cerci (upper pair of claspers) at the tip of the abdomen (whether paddle type or wedge type). Other marks that are often helpful include the presence/absence of a black line across the face, and the sizes of the pale spots on top of the abdominal segments (S), including the presence/absence of a spot on S10. Refer to the images of Aeshna species on the species pages of this website to compare shapes of thoracic side stripes and consult any dragonfly field guide for illustrations of the claspers (some guides are listed in the Resources Section).

Status-Global/State:

Global: G5     Wisconsin: S5    

Distinguishing Characteristics:

Males are readily separated from other darners by the combination of deeply notched anterior thoracic side stripes, no black line across the face (similar lake darner has black face stripe) and small bumps on top of the cerci near the tip of their paddle-type claspers (similar green-striped darner lacks fine bumps there, but magnification is needed to see if bumps are present). In Wisconsin, thoracic side stripes of Canada darner are usually mostly blue, but often with some green at their lower ends; Green-striped darner thoracic side stripes are usually all green. Females have thoracic side stripes either all green or mostly blue like males. Those with green stripes are very similar to female Green-striped darner. Separating females of the two species is not easy, and isn¬ít always feasible, but marks on the side of the thorax and base of the abdomen can be helpful.†

DuBois, R. 2017. Reliability of field marks for distinguishing females of Aeshna canadensis (Canada Darner) and Aeshna verticalis (Green-striped Darner). ARGIA 29(1): 40-43.

Description of Habitat/Range:

This species is common throughout southern Canada and the northern United States, and it is common throughout Wisconsin. Typical habitat includes bog-bordered lakes, boggy ponds, fens, and slow streams. Canada darners may be observed in feeding swarms with other mosaic darners in upland clearings, especially at dusk. It is probably the most common mosaic darner in the northern half of Wisconsin.

Flight Season:

Late May to early October, relatively early for an Aeshna. Prime time is July and August.


Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
<1%
(1)
6%
(35)
22%
(136)
35%
(214)
35%
(215)
2%
(13)
Shading illustrates monthly percentages of the total flight season records for the species. Each flight season record is a unique date/location/observer combination where one or more adult or an exuvia was recorded (excludes nymphs). The actual number of flight season records for each month is shown in parentheses.

Flight seasons begin earlier in the southern part of the state, often by a week or more. Also, flight charts may not be accurate for rare species because of few data available.
View user-submitted photos

(Click on photos to enlarge)
Photo of Male Canada darner
Male Canada darner. © Dan Jackson

Male Canada darner
Photo of Female Canada darner
Female Canada darner. © Dan Jackson

Female Canada darner
Photo of Female Canada darner
Female Canada darner. © Dan Jackson

Female Canada darner



This site is produced in conjunction with the Wisconsin Aquatic and Terrestrial Resources Inventory and sponsored by the Wisconsin Department of Natural Resources. The information presented on this site is subject to the Wisconsin Department of Natural Resources' Legal Notices, Disclaimers, and Terms of Use.