Hull Dragons 2020: September summary

Autumn is definitely on the air, after the warm and sunny days that have brought the dragonflies and damselflies out in the first three weeks of the month, cooler weather with northerly winds and more rain set in for the last part of the month. A total of 133 records from 8 species were submitted in September by 15 observers, covering 31 km2. Thank you all for your efforts. The survey is set to surpass the number of records submitted last year, with a total so far of 696 records. 

March of the Willow Emerald

The Willow Emerald Damselfly has expanded through the UK since 2009, after natural colonisation from Europe. A year ago Dick Shillaker found a male Willow Emerald at East Park, the first record for East Yorkshire. This year, we've had a number of records for the species in the Hull area, in fact, it has been the 3rd species in number of records for September after Migrant Hawker and Common Darter. A warm, breezy afternoon - one year to the day of the first record - I bumped into a mating pair, first flying and then settled on a buddleia branch, just under the pedestrian bridge at Abbey Way, over the Beverley & Barmston drain (top shot). Some distance away, a lone female basked on a Japanese Knotweed. A few days later, we had another set of records at a new location, Humber Bridge Country Park, where 6-7 individuals with two mating pairs in the same area and records for a number of days. A male was spotted at the Beverley and Barmston Drain by Beresford Avenue. The sudden increase in records from last year and their spread, and the number of individuals involved may suggest that the species may have been overlooked last year, when it might already have bred in Hull. Alternatively, there has been a massive influx of individuals arriving at suitable sites coinciding with the warm weather and southernly winds?

Female Willow Emerald Damselfly on Japanese Knotweed.

Beverley and Barmston Drain

I have been visiting the Beverley and Barmston drain regularly this year. It has been surprisingly good for dragonflies, with even a Hairy Dragonfly early in the year. The drain does looks like ideal habitat for Willow Emeralds: very slow flowing and with occasional willows over the water. 

A terrapin emerges from the blanket of duckweed

Moorhen sat on floating rocking horse.

A stretch of drain with overhanging willows.

This stretch of the drain has large trees on one side.

Abbey Way pedestrian bridge.

Beresford Avenue bridge.

Breeding Migrant Hawkers

September is peak breeding season for Migrant Hawkers. They reach maturity and males develop intense blue and yellow colours. Females also have more rich brown and yellow colours. Individuals may still be seen away from water, but as they mature, they are increasingly found by their breeding lakes and ponds where their behaviour becomes more focused on breeding. Males patrol areas by marginal vegetation, often hovering over this for some seconds before moving to prospect another area. Sometimes they enter marginal vegetation searching for females. If a female is spotted, mating ensues. I have been able to follow two mating pairs from the beginning. The pair flies away from the water and settles on trees or marginal vegetation, on a south facing spot. Although I've watched many pairs mating, in two instances I could watch a mating pair for a long time, since the initial capture of the female by the male. These two pairs remained mating for over 32 minutes and over 17 minutes (I didn't stay the full length of the mating so these will be underestimates). I have been unable to find any information on the average mating length in the species. In a previous post I have covered the mating system in this species, which concludes that non-territorial species, like the Migrant Hawker, where sperm competition is likely to be more intense, mate for longer, and is nice to see that my observations match this expectation.

A resting male in full breeding colours.

Mating pair at Noddle Hill lake.

Migrant Hawker ovipositing on floating branch at Foredyke Green Pond, an unusual ovipositing spot for this species.

Female Migrant Hawker ovipositing on branched burr-weed leaves, by the water. 

Brown Hawker ovipositing on floating wooden board.

Species recorded in September

Migrant Hawker, 74 records.

Common Darter, 30 records.

Willow Emerald Damselfly, 11 records.

Southern Hawker, 6 records.

Small Red-eyed Damselfly, 2 records.

Blue-tailed Damselfly, 1 record.

Ruddy Darter, 1 record.

Brown Hawker, 1 record.

Hull Dragons 2020: August summary

We've had some excellent dragonfly weather this August, with plenty of warm, sunny days. Although the last week had plenty of wind and rain, it was often warm enough even when overcast to entice some dragonflies out, until the very end of the month, dominated by cold northerly winds.

Odonata highlights

We've got a whooping 200 records from 12 species in the month of August. These are from at 35 1 km squares for August from 13 recorders, thank you all who have contributed records!

The season is over for many species (Hairy Dragonfly, Large Red Damselfly, Broad-bodied Chaser, Banded Demoiselle), and is coming to an end for others: Azure Damselfly, Four-spotted Chaser or Black-tailed Skimmer.

Migrant Hawkers (top shot) have been the top species, with a third of all, followed by Common Darter,and Blue-tailed Damselfly. Although there has been no new species added for the year in August, there is a chance we may still record Willow Emerald as the first records las year were in September.

Brown Hawkers

Brown Hawkers bumper year has continued, they are the 5th species in number of records for the month. In July many observations involved patrolling males on territory, but in August, ovipositing has been observed, twice at Foredyke Green (on the muddy shore, on floating wood and on floating polystyrene) and also likely ovipositing behaviour at East Park.

Female Brown Hawker rests between ovipositing bouts.

Oviposition on polystyrene.

Migrant Hawker

Most records involving hawkers away from water, hunting at 4-5 m high, sometimes in twos and threes are highly likely to be Migrant Hawkers in our area. Two or three individuals have been present regularly in my garden, and I was lucky enough to spot one of them basking quite low on a potted olive tree. It allowed for very close approximation.

A male Migrant Hawker Photo taken by my son with his mobile phone. 22nd August.

And a female, from the 31st of August.

There were several exciting Migrant Hawker highlights. One of them was to find a total of 6 exuviae at East Park. Exuviae is the formal name for a moulted larval skin, which can be found on marginal or emergent plants, after the adult has emerged. The presence of exuviae in a site provides evidence that a species has successfully bred in a site. As far as I know this is the first confirmation of successful breeding in the city of Hull after last years observed ovipositing in several sites.

Migrant hawker exuviae in situ.

Another interesting observation involved an individual flying underneath an ivy overhang and settling on it, moments before a rain shower. I found another individual near it. I wonder what makes the hawkers seek refuge, maybe the sudden darkening of the sky?

I was at Pearson Park Wildlife garden during muggy, but cloudy weather. During a sunny spell followed by a strong breeze, at least 20 migrant hawkers took to the wing and started hunting over the garden. This is the largest number of individuals I have seen of this species.

Finally, I have been able to observe Migrant Hawkers active during cloudy weather and temperatures as low as 13-14 oC. They might be able to achieve temperatures high enough for flight by basking during brief sunny spells. When windy, they forage around trees at the lee side of the wind in sheltered, sun-facing spots.

Blue-tailed damselfly mating behaviour

The following photo show a mating pair of Blue-tailed damselflies. In this species, copulation is very long, up to 8 hours and in dense populations a form similar in colour to males increases in frequency, as these females avoid the costs of prolonged copulations.

Females oviposit alone. I was at Foredyke Green site about to take a photo of an ovipositing female, when a male came out of nowhere, knocked the female over, and immobilised her by holding her with jaws, legs and mating appendages. The following is a series of photos documenting how the male gains hold of the female, in the last photo he has already adopted the tandem position. I wonder had I only seen the last part of the behaviour, with the female already on the water, if I would have concluded that this was an example of a 'damsel in distress' being rescued by the male. I'm glad I got the whole sequence!

Small Red-eyed Damselfly

The Pickering Park and East Park populations are thriving: hundreds of individuals were present at East Park model boating lake and some as well in the main lake. A record in a new location was at St Andrews Quay Pond. The records show a establishment of the species in both large parks at Hull. Copulation and ovipositing was observed at East Park and Pickering park.

Small Red-eyed Damselfly at Pickering Park.

Small Red-eyed at East Park.

Small Red-eyed at East Park.

Copulating Small Red-eyed damselflies at East Park.

Best sites this year so far:

• East Park: 13 sp.
• Noddle Hill LNR: 12 sp.
• Foredyke Green Pond 11 sp.
• Oak Road Lake 9 sp.
• Pickering Park 8 sp.
• St Andrews Quay Pond 8 sp.
• Beverley & Barmston Drain 7 sp
• Paull Holme Strays 7 sp.
• Humber Bridge Country Park 7 sp.
• Pearson Park Wildlife Garden (closed due to COVID, but surveyed with permission) 6 sp.
• Willerby Carr Dyke, 6 sp.
• Beverley & Barmston drain, 6 sp.

Other species Gallery

Teneral Common Darter.

Common Darter in obelisk position

Emerald Damselfly at Noddle Hill LNR.

Ruddy Darter at Noddle Hill NR.

Southern Hawker at Noddle Hill LNR

Ovipositing Emperor at Foredyke Green pond.

Common Blue Damselfly.

A late Azure damselfly. Numbers have been steadily falling during the month of August.