Urban birding at Hull: Sculcoates week 30

A sunny, warm morning, I looked forward to a visit to the patch, hoping in particular, to add Gatekeeper to the butterfly list. As I got to the patch boundary, 5-6 Swifts started chasing, trilling, low over the street.

 

I didn't have to wait long to see my first Gatekeeper, sunnying itself on the verges of the footpath by the drain. 

Gatekeeper.

Speckled Wood.

Comma.

Green-veined White.

Nice to see just half a meter has been mowed on the sides of the footpath/cycle lane by Barmston drain, the verges are rich in wild plants and teeming with insects, including Small Tortoiseshell caterpillars (and I presume pupae) a good compromise between access and nature.

Two Small Tortoiseshell Caterpillars in search of fresh nettles.

Drinking and bathing

There appear to be a group of birds in a particular bush at the other side of the drain. They are a mixed bunch: Chiffchaff, Lesser Whitethroat, Wren, Robin, Blackbird, a family of Goldfinches, Woodpigeon and Dunnock. I think there might be a cat or another predator on the ground. I wait and keep identifying birds and adding them to my list, one of them is a young Sedge Warbler! the first one I actually see on the patch, I heard one singing earlier in the season. A bird, all soaked up, flies onto a branch to dry. They I think that the reason all these birds are there is that there might be a place where they can drink and bathe. It has been very dry in the last couple of weeks and the drain is not easy to access for a drink due to the marginal vegetation and how steep it is.

Lesser Whitethroat and Sedge Warbler.

Robin.

Young Sedge Warbler.

Lesser Whitethroat.

Soaking Blackcap.

Cemetery

In the Sculcoates N Cemetery a Southern Hawker is feeding on the main path, but almost immediately it stops hanging from a leaf, maybe it has hunted something as it seems to be holding something, maybe a moth? 

There are many Gatekeepers and whites, but no Skippers. In a corner with Tansy, I search and find some Colletes bees, likely daviesanus.

Colletes on tansy.

In the Air Street cemetery, a Holly Blue flutters over a bed of ivy, but doesn't stop and flies high into the trees. I search for the small Elms growing in the corner, but since the last time I saw them a couple of weeks ago, one of them has died.

A woodpigeon struggling with a mishapen branch. It left it on the ground.

Before leaving I looked for dragonflies on the drain. An emperor and a Brown hawker were disputing a stretch of drain under the bridge. On the elevated ground, a Migrant hawker was hunting, and I was lucky as it stopped quite quickly for a rest, the first Migrant Hawker I photograph this year. I saw two others today. There seems to have been an influx in Hull in the last couple of days.

Migrant Hawker.

Brown Hawker over the drain.

Two species of grasshoppers on a small patch of brownfield with many wild carrots at Temple street.

Lesser Marsh Grasshopper, Chorthippus albomarginatus.

Common field grasshopper, Chorthippus brunneus.

July Wetland Bird survey urban River Hull

 The high tide at 7:45 marked the time for my third Wetland Bird Survey count at the urban river Hull stretch. The season is going get interesting soon with returning waders. I walked to Scott Street bridge site, the first view point over the river Hull. A family of Lesser black-backed Gulls was on a roof. The first of several today. Some Black-headed gulls were also on the river. 

A large flock of pigeons feeding on spilled grain on a factory.

Lesser black-back gull juvenile begging.

Next is a section where the river is not visible. I take a quick detour around the Charterhouse cemetery.

A squirrel on a poplar by the Charterhouse cemetery.

The river becomes visible again at North Bridge. Looking North.

I cross the bridge. Early Sunday there is very little traffic. I join the footpath. The blackberries are looking good, still a bit sharp, maybe a couple of days out of being ripe. When I take a photo of them I notice the Vapoureur caterpillar.

Vapoureur caterpillar.

Nothing too exciting on the river between both bridges, but from Drypool bridge I see a Black-headed gull roost or about 30 on the roof of the Royal Mail depot. I'm glad I found this, as the rooftop is invisible once you cross the bridge. Must check it every time I do the WeBS count.

As I walk along the river bank, heading downstream, I regularly scan the rim of the flood defences, hoping to find some Mallard, or Redshank. I scan distractedly their usual roost site by the buoy shed, surely they can't be back yet, but they are! Ten of them in a neat line, looking like they are still settling down, stretching, preening, mostly awake, quiet. I scan their legs and can't see a ring (but Andy Gibson notices one in a photo I later share on twitter). I meet Carol, who walks along the river most days enjoying the wildlife and notices I'm watching with binoculars. We shares the joy of watching the returned Redshank. They must be just back from their summer grounds.

A Black-headed gull checks its feet by the Truelove installation.

I walk by the Dock stage and some faint peeping draws my attention: it's a moorhen chick calling. It's parent dutifully brings it some food. I think it's the first time I see moorhens here.

Moorhen and chick at The Dock Stage.

I always see a pair of Carrion Crows by the tidal barrier (top shot), a few weeks ago they had young, today I found the unusual location for their nest. They must have great views when incubating!

Pair of crows with their nest at the tidal barrier.

A Lesser black-back young recently fledges, still some down on its head.

More LBBG young.

Seventeen Mallard roosting mostly on the saltmarsh south of Scale Lane bridge. Some look like young of the year. This female watched intently as I scanned the saltmarsh.

A final highlight is watching a Peregrine, flushing the pigeons, swerving around a building rooftop, exhilarating!

On the walk back there are sunny spells and I do three butterfly counts on the way home, including on Milky Way. Two Migrant Hawkers hunt at the Artlink, the first I see in Hull this year.

Urban birding at Hull: Sculcoates week 29

A cloudy, mild day at Hull. The river is just past a very high tide. As I walk along the drain, a dozen Lesser Black-back gulls start alarm calling, flying over me. A recently fledged young whistles while the parents follow it nervously. The noise is quite loud and piercing, like a fire-alarm. I wonder if raptors find it annoying too and avoid gull colonies not only for the mobbing itself, but also for the chorus of alarm calls. For this reason, and also because it's cloudy and I'm probably not going to see many insects, I decide not to visit the cemetery, which is right next to a gull colony. As I zoom into a youngster on the paint factory (top shot) the adults appear to see me as danger and fly off to call over me!  

A young Lesser Black-backed gull on its colony.

I find three Swallows on the patch. A pair of Greylag flies over. There has been a few weeks with no flyovers, as the geese moulted and stayed in their breeding sites.

Woodpigeon with stick.

The rowan berries are maturing. This Woodpigeon flew to the rowan and picked a couple of berries, as if to test how ripe they are. It flew off afterwards, maybe not good enough yet.

Goldfinch family. I've started to see flocks, possibly as families merge and become more mobile in search of seeds.

Song thrushes are not singing, but I managed to see this one by the drain.

The river Hull running high.

Two recently fledged gulls (Herring or Lesser black back gulls).

As I'm about to leave, I hear a Swift scream and as I look up I see a chase of five, a nice end of the visit this week.

Urban birds at Hull. 23. Swift

Swifts are one of the most urban of birds during the breeding season. A few pairs use cliffs on the coast or quarries and even cracks in dead trees, but the vast majority nest under roof tiles, eaves and crevices in the walls of buildings. They have large, narrow and curved crescent-shaped wings and forked tails, and are dark brown, with a paler throat patch. They are very aerial birds, only landing to nest: they sleep, mate and feed on the wing and they are the fastest recorded bird in level flight. Swifts 6000 mile long round trip annual migration has been researched using geolocators attached to their bodies with tiny harnesses. The data revealed a long-distance migration pattern to sub-saharan Africa with the birds almost always on the move across several regions to take advantage of the rains and food availability. In the autumn migration they move across to France, Spain and then along the north African coasts. The winter is spent over the Congo and Mozambique rainforests. On the way back to their breeding quarters in early spring the birds stop-over in Liberia for a week or so, presumably fattening up on seasonally plentiful resources. 

Swift pair. Pairs often fly together as they feed.

A Swift chase. Parties of Swifts chase screaming around their breeding colonies. The trilling calls of the chasing birds are a feature of summer.

Status and distribution in Hull

In Hull, Swifts are summer visitors and passage migrants. I look forward to the first Swifts returning to Hull on the first or second week of May. The yearlings and two-year old birds won't breed, but they still migrate to pair up and find potential nest sites (top shot). The non-breeders arrive a bit later and migrate back earlier, in the first or second week of July. Then, there is often a peak of Swifts in the air, Swifts are more vocal and the chases are more spectacular. Numbers then decline markedly during August, as the young are reared and they start their migration season. They are with us barely for three months of the year! Swifts are widespread in Hull. Lakes and rivers and wetlands not only in the city but in the surrounding area support dense insect populations and attract feeding swifts. Several thousand gather over the reservoirs at Tophill Low in June, swirling over the water as they feed, coinciding with the mass emergence of non-biting midges.

Clouds of Swifts feeding over the Tophill D-reservoir. 10th June 2019. It was a marvel to behold!

A survey in May 2006 revealed that Swifts were found in 12 of the 90 1x1 km squares in Hull (Tophill Low 2006 report, RL et al). A repeat survey using the same technique would be welcome to assess the size of the population in Hull.

Conservation and management

Swifts have suffered strong declines in recent decades. Since 1994 we have lost population 60% of the Swifts in the Yorkshire and the Humber area as estimated by the BTO/JNCC/RSPB Breeding Bird Survey. The Swift has recently been moved from the Amber to the Red Listed in the Birds of Conservation Concern 5. 

BBS population trends for Swift.

The decline has been attributed to a loss of nest sites due to insulation and renovation or demolition of old buildings and modern building designs which lack suitable nest sites. In addition, stark insect declines in recent decades due to pesticide use might have contributed to Swift declines. Management is three pronged: installation of swift bricks in new buildings, being mindful of swifts during house renovations and monitoring of populations. Swifts are very mobile and fly away from storms and poor weather. They can also take long, 50 mile round trips in search of food for their chicks, so the usual monitoring methods might not be very accurate to estimate local populations. An app which takes into account Swift behaviour, Swift Mapper has been developed by several conservation organisations in order to locate and monitor local colonies.  

More information

Henningsson, P., Johansson, L. C. & Hedenström, A. How swift are swifts Apus apus? J. Avian Biol. 41, 94–98 (2010)

Appleton, G. 2012. Swifts start to share their secrets. BTO News. 

Åkesson, S., Klaassen, R., Holmgren, J., Fox, J. W. & Hedenström, A. Migration routes and strategies in a highly aerial migrant, the common swift Apus apus, revealed by light-level geolocators. PLoS One 7, e41195 (2012).

Åkesson, S. et al. Evolution of chain migration in an aerial insectivorous bird, the common swift Apus apus. Evolution (2020) doi:10.1111/evo.14093

Lack, David. 1973. Swifts in a tower. Chapman and Hall.

Stanbury, A., Eaton, M., Aebischer, N., Balmer, D. & Win, I. (2021) The status of our bird populations: the fifth Birds of Conservation Concern in the United Kingdom, Channel Islands and Isle of Man and second IUCN Red List assessment of extinction risk for Great Britain. British Birds 114, 723–747.