Migrant Hawker

Aeshna mixta

This relatively small late-season hawker is often difficult to pin down as it hunts open land and woodland edges. Fairly widespread and usually more numerous than other hawkers, they can be encountered anywhere from late July right through to November (if the weather holds) well away from water, and are annual visitors to my garden. Usually can be found hunting along the Derwent Walk Country Park, around Clockburn Lake and Kite Hill, Gibside, but the most regular spot is the fields adjacent to Far Pasture Access Road in afternoons and early evenings.
Kibblesworth and Shibdon Pond are two sites they are also seen regularly at but I find Far Pasture in late summer to be the most reliable, if not often the best for photography, they can be observed hawking the fields and patrolling the ponds.
Shibdon Pond, I have discovered, is best for finding perched Migrants, just walk along the boardwalks and inspect the reeds and bushes, best before they've had time to warm up properly in the morning. 

Migrant Hawker (mature male)
Both sexes closely resemble their common hawker counterparts. There are
many subtle differences but size difference should be apparent and the
common hawker male is usually a lot darker in overall colouring.
This photo shows the diagnostic yellow golf tee marking at the top of
the abdomen, and the antehumeral stripes are no more than pips.
Mature male
Another view
Immature males are a pale lilac colour (where blue on mature) and take 7-10 days to reach maturity.

Immature male
Blue markings paler or more lilac in colour than when mature
 

This close-up shows how beautifully marked
the immature is, grey brown eyes are a
telling factor in immatures. 

Profile view of immature male

Close-up shows the thorax stripes and the grey/brown eyes

In cool weather, especially mornings, the mature males return to the paler colouring similar to the immature before warming up.
Females are similar to the males, have a slightly thicker abdomen and yellow spotting on brown.

Female Migrant Hawker
Distinctly different from the male in colour and shape, more likely
confused with a female Common hawker, though is a lot smaller
 

Close-up shows better the yellow on brown
colouring and the chocolate brown eyes.
In profile the bright yellow thorax stripes and at the base
of the abdomen are apparent on the female but in silhouette
the telling factor is the club-like tail end, whereas the male (below)
appears slightly tapered.  



In flight the finer points of ID are not easy to see but size should still
be apparent and whereas common hawkers usually hunt alone in
woodland rides, migrants hawk open fields at head height, and woodland edges
up to treetop height, often in numbers. 


Hanging vertically in the sunshine.   
 
At the breeding site the males search for a female in the marginal vegetation,
often hovering, and perching horizontally like this. They aren't
territorial and don't show much aggression when encountering another male.     
 Males visit water in the middle of the day, patrolling a section of shoreline low over the water. Any  female encountered will be chased down, seized and paired up in flight, before settling in vegetation for a lengthy copulation. the female then usually oviposits alone.
Eggs lie dormant over the winter, hatch in spring and develop rapidly to emerge from July onwards.

No comments:

Post a Comment