Friday, 16 September 2011

ID comparison file : Common/Migrant Hawkers (male)

Another whinge about the weather. Wind, rain and latterly the remnants of a hurricane mean only three reports in total filtering through to DragonHunter HQ from the network of scouts since the beginning of September :
Migrant hawker on 4th at Sled Lane Pond

3 migrant hawkers, 2 common hawkers at Kibblesworth on the 5th
 Migrant hawker and two female southern hawkers were photographed at Shibdon Pond on the 6th
(all courtesy of Gatesheadbirders.co.uk)

Note: Still no sightings of Black Darter from anywhere in the borough, possibly due to no-one looking because of the much maligned weather, but still not good news
.
But since we now have some half-decent shots of a male migrant hawker I’ll do a quick comparison with that of the common hawker:

In flight from side-on it's difficult to make a distinction between these two.
Migrant Hawker (top) Common Hawker (bottom)

But from this angle you should be able to make
out some important diagnostic features. Look for the
yellow costa of the common hawker, the pale golf tee
shape at the top of the abdomen of the migrant, and
the difference in the size of the antehumeral stripes
at the front of the thorax, thin stripes of the common (top)
but mere pips on the migrant (bottom)

Some flight jizz pointers if you don't get a perched individual to inspect :

Common Hawkers are tireless flyers and so notoriously difficult to get a good look at (never mind photograph) perched up. We were really lucky to encounter those mating pairs a few weeks back.

Migrant hawkers are noticeably smaller (around 5.5 to 6.5 cms in length compared to the commons nearer 8.0cms) in fact if just glimpsed in silhouette can be initially mistaken for darters, and are much more likely to be encountered away from ponds as they forage along woodland edges next to open land, where there can be several hunting the same stretch, as opposed to the more solitary common hawker which will hawk along woodland rides rather than be out in the open.
Migrant hawkers also fly at a cruising height of around six feet, only veering from this height to chase a meal, the common hawker has a much more up and down hunting pattern. Also a common hawker won‘t approach you like other hawkers indeed is more likely to give you a wide berth, whereas the migrant will treat you as if you were any other obstacle in its path, veering away at the last moment, or like happened to me the other week will hawk for midges around your head.
( But still not as confidiing as the Southern Hawkers which will deliberately investigate you and occasionally even land on you).

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