Hull Dragons: August summary

The dragonfly season has been in full swing, particularly during the very warm Bank Holiday weekend. Thirteen species and a total of 130 records from 23 km squares have been submitted so far to iRecord during August. Seven recorders have contributed to these records. During the last part of the month a number of species were still on the wing, although the records were dominated by Common Darters and Migrant Hawkers, two late, abundant and obvious species that also roam away from water. Both species add squares to the survey that don't necessarily hold breeding sites.
  Choosing highlights hasn't been easy, but these are some.

 Small Red-eyed Damselfly
To the thriving population at East Park we added Pickering park as a new site for the species, where many individuals and ovipositing was confirmed. A few other scattered records are evidence of the rapid range expansion of this species.

Migrant Hawker
A great year for Migrant Hawkers. They have been plentiful, with almost 50 records submitted to iRecord to 6th of September, compared to 18 last year. More excitingly, breeding evidence was obtained, with multiple patrolling males on several potential breeding sites with mating pairs at Pickering Park, Foredyke Stream, Beverley and Barmston Drain, and oviposition observed at Foredyke Stream.

Southern Hawker
A total of 22 records have been submitted for this species this year, compared to 4 last year. The Southern Hawker (top shot and above) is a recent colonist that has only been in the recording area since 2007, but is now well established, with records from 12 sites and evidence of breeding (oviposition and emergence) in several of them.

Male Black Darter near St Andrews Quay, 2012. Photo by Barry Warrington, used with permission.

Black Darter
A record of a male was submitted by Barry Warrington of this rare darter on the East side of the Yorkshire Wolds. This is a notable record as there are only a handful of records in the area, the first one from 2011 at Priory Fields, the second from the Beverley and Barmston Drain in 2013. Barry has found Black Darters in the same area, near St Andrews Quay, in 2012 (above) and 2016. Records of this species probably represent dispersing individuals, as the species breeds on boggy, moorland or heath ponds not present in our recording area.

List of species recorded in August

1. Migrant Hawker.
2. Southern Hawker.
3. Brown Hawker.
4. Common Darter
5. Emperor Dragonfly.
6. Common Blue
7. Blue-tailed Damselfly.
8. Small Red-eyed.
9. Red-Eyed Damselfly.
10. Azure Damselfly
11. Ruddy Darter.
12. Emerald. Foredyke Green.
13. Black Darter.

In the wider area: Willow Emerald expansion

Emerald Damselfly. Mature male.

Willow Emerald male. Note lack of blue 'pruinescence', pale pterostigma with black margins and pale abdominal appendages. On side view a spur on the thorax is distinctive. Note eyes are not blue. 

Records of Willow Emerald Damselfly from Lincolnshire and a record from North Yorkshire means that there is a possibility this rapidly expanding species may make it into Hull in the near future. Fortunately, it is a late flying species, active until October, so it is worth while keeping an eye for it. The photo above was taken in a London park during the bank holiday weekend.

Migrant hawkers scramble competition

I'm used to watching migrant hawkers foraging over gardens, leafy streets and sheltered woodland rides, some times in groups. They are immature individuals, gathering energy away from water. Migrant Hawkers, unlike other hawkers, mature slowly, and will move to suitable breeding sites after their long immature period. During this past week I've watched them in their breeding sites in lakes and drains, where mating and egg-laying takes place.

A mature male rests briefly between bouts of searching (Pickering Park, 27th August) 

Males at the breeding site 
At one of my local parks (Pickering Park) last week, dozens of Migrant Hawkers sat or patrolled alongside marginal vegetation around the lake. The males, now fully mature and showing their bright blue spots and eyes and side yellow-green stripes often hovered in a spot, or explored the vegetation, flying well into it, searching for females.

A typical hovering male in a clearing at the marginal vegetation (Pickering Park, 27th August), offering them good views.

Mating
I saw no females, until one was captured by a male: no preliminary or courtship, the male just tackled her and positioned himself to grab her by the head. The female is then able to curve her abdomen and mate, retrieving sperm from the male's secondary genitalia at the base of the abdomen, forming the 'wheel position'. They may fly in wheel position very fast, zigzagging alongside the marginal vegetation edge or briefly rising into the air, before settling on vegetation (above).

Ovipositing female (Foredyke Stream, 1st September)

The moment when the male passes by, and sees the female.

The pair, mating.

Oviposition
A couple of days ago I watched a patrolling male on a ditch doing its usual patrolling routine, rising to inspect any passing individual, even paying attention - briefly rising - to birds flying over. A mated female arrived, unnoticed, and started laying eggs on live leaves well above the water line, I'd say over one metre over the water. She checked leaves and unsheathing her ovipositor, started laying into them (the eggs will overwinter inside the plant leaves, where they are protected from predation). After a couple of minutes, the male noticed her, tackled her and mating ensued. This time the pair settled briefly on plants, which allowed me to take a shot (above). Mating in Migrant Hawkers is longer than in other territorial relatives.

Two males resting near each other (Pickering Park, 27th August)

Nonterritorial males
This species is notoriously non-aggressive, even at the breeding sites. Males will even rest within view from each other (above). A patrolling male will swiftly rise to check a passing one, but the interaction is suggestive of them 'checking' that they are not a female, and letting the other individual go their way if it's a male. There is no defended territory, just males congregating on suitable ovipositing sites and searching for females, a type of mating tactic called 'scramble competition'. This appears to be the reason behind the long copulation. A territorial male mating for a long time may lose the territory to an invader, or miss extra mating opportunities. A nonterritorial male has less to lose, and therefore makes sure that he fertilises as many as possible of the females' eggs, possibly by taking time to remove any previous sperm before transferring his transfer. These patterns have been shown to stand when the copulation duration of territorial and nonterritorial drogonfly species were compared, but I haven't found specific data on the Migrant Hawker. To illustrate the pattern, the Emperor, a territorial species, copulates for an average of 10 min, while the Common Hawker, a non-territorial one, copulates for an average of 67 min. Of course, this lengthy copulation is not necessarily to the benefit of the female, who may be already mated, as the female already laying eggs, and therefore this sets the stage for the evolution of female counter-tactics, such as visiting the water as little as possible and avoiding males if they can, something I have covered before at Bugblog.

More information
Córdoba-Aguilar, A., Serrano-Meneses, M. A. and Cordero-Rivera, A. Copulation Duration in Nonterritorial Odonate Species Lasts Longer than in Territorial Species. Ann. Entomol. Soc. Am. 102, 694–701 (2009).

Hull Dragons: July summary

July is peak dragonfly season, most of the early species are still on the wing, and the last of the high summer species have emerged too. Hull Dragons has now a total of 180 records in iRecord, from 34 km2 surveyed (28 of them in July) yielding a grand total of 15 species. All but Broad-bodied Chaser, an early season species, have been recorded during July at iRecord.

Survey coverage: 34 km2.

Four new species have been added to the survey this month: Southern Hawker, Common Darter, Brown Hawker and Small Red-eyed Damselfly. Evidence of breeding has been obtained for all four but Brown Hawker.

Southern Hawker
The first record of Southern Hawker was at Pearson park Wildlife Garden pond. A number of fresh exuviae were collected between the 2nd and the 8th of July from the emergent vegetation in and around the pond.

Southern Hawker exuviae, Pearson Park wildlife garden.

Two exuviae and observations of an individual getting into a house were obtained at a private Avenues pond. Other records include an individual flying by Oak Road and two or three at Noddle Hill Lake.

Immature Southern Hawker at Noddle Hill Lake.

Banded Demoiselle

The excellent Banded Demoiselle year continues, with more records and additional sites for this species by the River Hull at Thearne, at Mill Beck, Cottingham and at the Boating Lake at Peter Pan Park (Costello Stadium).

Female Banded Demoiselle by the River Hull at Ennerdale.

Emperor Dragonfly
After a few sightings in the last week of June, it is peak season for this species, which has now been recorded at 10 sites. Males were patrolling and defending territories at East Park, Pickering Park, Foredyke Green, Ennerdale South pond and Beverley and Barmston Drain. A female was observed ovipositing at Ennerdale South pond

Male Emperor by the Beverley and Barmston drain.

Female Emperor ovipositing, Costello Stadium boating lake.

Black-tailed Skimmers
The first Black-tailed skimmer record was at the end of June, but it is in this month that they become more common. They have been recorded at 4 sites, with 8 records: Ennerdale South pond, East Park, Noddle Hill LNR and a private avenues pond. Ovipositing was observed at Ennerdale South Pond.

Ovipositing female and guarding male Black-tailed skimmer at Ennerdale South Pond. The male confronted the resident Emperor while the female oviposited.

One of several territorial male Black-tailed Skimmers at East Park.

Azure Damselfly

Azure Damselflies have now been recorded in 13 km2. Evidence of breeding in the form of mating and ovipositing has been obtained in several sites.

Azure Damselflies mating, Pearson Park wildlife garden.

Ruddy darter

Ruddy darters have been found in Noddle Hill LNR, Oak Road Lake, Midmeredales Pond (several tenerals) and a private pond in the Avenues.

Ruddy Darter, Oak Road Lake.

Common Darter

The first Common Darter in the area was at Ennerdale S Pond on the 4th July, where several tenerals were found in the vegetation by the pond. More tenerals and darter exuviae were found at an avenues private garden where both Ruddy and Common Darters have been recorded. At least two individuals and three exuviae were found at Pearson Park Wildlife Garden. This species has a long flight season and roams away from water before settling to breed so hopefully more records will be added as the season progresses.

Common darter, private avenues pond.

Blue-tailed damselfly

No matter the weather, even during cloudy or muggy days or the habitat, which includes polluted water or fish ponds, the Blue-tailed damselfly always saves the day. I was pleased to find the 'rufescens' female form at the pond in the Museums Garden in the city centre, where the species is very abundant. This form also occurs at East Park. We now have records from 18 squares in the recording area.

Small red-eyed damselflies

The first sighting of this species this year was at East Park, with dozens of pairs ovipositing in both main lake and boating lake on 13th and 25th of July. Two individuals were recorded at St Andrew’s Quay pond and there is also a record at a garden pond at Skidby. The new locations indicate that this species is likely to become more common and widespread.

Resting male.

Small red-eyed damselflies ovipositing, East Park boating lake.

Red-eyed Damselfly
More records for this species were obtained for East Park and Noddle Hill. A teneral female at Noddle Hill provided evidence of successful breeding at this site.

Red-eyed Damselfly, Noddle Hill Lake.

Teneral female Red-eyed Damselfly, Noddle Hill lake.

Dragonflies to watch for in August

In this fourth and last instalment of the series on dragonflies to watch out in and around Hull I present five species that have their peak flight season in August.

13. Southern Hawker, Aeshna cyanea. A large and colourful dragonfly which is hard to miss, as it likes to hawk low on shaded paths. It has a peculiar behaviour consisting in approaching people as if it was curious and was checking you out! It starts to emerge in mid-June and flies until late October, with a long peak from mid July to early September.

15. Ruddy Darter, Sympetrum striolatum. A small, compact dragonfly. Legs are black in both sexes (unlike Common Darter, see below). Males are blood-red and there is no yellow band on side of the thorax, which is reddish brown. It flies from mid June to early October. Peaks in July-August.

16. Small red-eyed damselfly, Eryhthroma viridulum. A small damselfly with red-eyed males. Close examination or photos are ideal for identification, as it differs in the pattern of blue in the tail from the closely related Red-eyed Damselfly. Short and late flight season from mid July to early September, peaking in mid August. Known from Oak Road Lake and East Park. Recent colonist, increasing its range so there is potential to discover new sites.

13. Migrant Hawker, Aeshna mixta. The first individuals tend to appear in the last week of July. Peaks end of August and has a long season, extending until November if weather is mild. It has a long immature stage and wandering habits away from water, which means that it is a species easy to record even in pond-less gardens. It hunts at tree canopy level. Smaller than other hawkers in the area. Individuals can hunt in small parties, with no signs of aggression, often resting near each other, hanging from their perches.

14. Common Darter, Sympetrum striolatum. The commonest darter in our area. They have a yellow stripe alongside each leg and yellow panels on the side of the thorax. Eyes are green or red on top and yellow below. Males are orange-red (above) with two yellow panels on the side of the thorax. Females have an all yellow side of thorax (below). Late and long season, from June until November, peaking at the end of August.

Hull Dragons: June summary

This month we've had mostly cool, breezy and unstable weather with plenty of rain, which perked up in the last few days, when it was very hot. Sunny days (better: spells!) were few, short and far between, not ideal for planning dragonfly surveys. Despite this, sightings have slowly built up and overall, eleven species have been recorded from 17 km2 in the city and surroundings. To the five species seen in May (Broad-bodied Chaser, Azure Damselfly, Blue-tailed Damselfly, Common Blue Damselfly and Red-eyed Damselfly) we have added six more: Banded Demoiselle, Four-spotted Chaser, Emperor Dragonfly, Black-tailed Skimmer, Ruddy Darter and Emerald Damselfly. These are only including the records submitted to iRecord: I'm hoping to obtain the dragonfly records submitted to the BTO through their popular Birdtrack app, later in the year. So far there are 103 records submitted to iRecord.

Banded Demoiselle
A total of 5 Banded Demoiselle individuals (top, male just by Oak Road Lake) have been sighted from four km squares in the River Hull between Clough Rd and the northern boundary of the city. This species is becoming common upstream, between Tickton and High Eske, and has been a very nice unexpected addition to Hull Dragons. The only previous record of this species in the city boundary was of Noddle Hill in 2015, submitted by Jen Woollin.

Red-eyed Damselfly
The Red-eyed Damselfly has been recorded from three sites this year: Oak Road Lake, Noddle Hill and East Park. I believe the East Park is a new site for the species, although there is no evidence of breeding there as yet.

Black-tailed Skimmer
Thank you to Andrew Chadwick for submitting this record from his garden, the first recorded Black-tailed skimmer of the year for Hull Dragons.

Emerging Broad-bodied chasers
It was worth keeping a close eye on the Pearson Park wildlife Garden.

Freshly emerged Broad-bodied chaser, 23/6/2019, 9:47am.

In the wider area...
There has been an influx of Vagrant Emperors, Anax ephippiger on the east coast, with records at Spurn, Flamborough and Donna Nook, so well worth keeping our eyes open for what may come our way!