Portway Hill – Green Hairstreak Search, 25th May

On a dry and mostly sunny May morning, 27 wildlife enthusiasts assembled just inside the entrance to Bury Hill Park off the A4123 Wolverhampton Road in Oldbury, for our walk entitled ‘Portway Hill – Green Hairstreak Search’. The route planned initially involved the ascent of the grassy slope of Bury Hill Park, which at this time of year is dotted with numerous umbels of white Pignut flowers. Small numbers of Chimney Sweeper moths have been seen here in in the past but council grass-cutting restricts this moth to a few small areas where the tractor’s grass cutting blades are unable to reach. At the summit of Bury Hill Park the ground levels out and excellent views of the surrounding urban landscape can be seen. Once everyone had gathered together, we followed the path that descends into and through the oldest of the Portway Hill quarries dating back to the late 1700s. A Speckled Wood butterfly flew by, but despite a brief appearance by a brownish-coloured butterfly or moth that quickly disappeared into the dense vegetation, which we thought might have been a Green Hairstreak, nothing came of it.

This track eventually opens out onto the lower part of the land owned by the Wildlife Trust for Birmingham and the Black Country, known now as Rowley Hills Nature Reserve. The group by this time had split up into two, with the serious entomologists straggling behind searching the vegetation for insects which, on what was now turning into a very pleasant day, were becoming quite active. With such a knowledgeable group of people very little went unnoticed, and soon Dock Bug, Hairy Shieldbug and Bishop’s-mitre Shieldbug were found. Discovery of a plant bug with distinctive orange and black markings, black legs and black antennae by one of our group, was later confirmed by Ecorecord as new to Birmingham and the Back Country. Corizus hyoscyami, sometimes called the Cinnamon Bug or Black and Red Squash Bug was until quite recently only locally distributed in sandy habitats around the coasts of southern Britain, but for reasons unclear it is now rapidly extending its range to a variety of habitats inland.

Heading in a south-west direction the leading part of the group paused at the exposed cliff-face where spheroid shapes peel off in layers during weathering, and good examples of columnar jointing, caused by cracks which formed when the magma originally cooled and contracted, can be seen. It was here that a Green Hairstreak made an appearance, alighting on an Oxeye Daisy flower just long enough for two or three of the party to take a photograph. Soon it was gone and for those at the back, sadly they were not to see a Green Hairstreak, our main quarry, as no further sightings were made during the walk. We did however all get a good view of the Small Copper that obligingly settled on a nettle leaf in front of us. Not the freshest of specimens, with a piece missing from the top corner of one wing, but nonetheless always a pleasing little butterfly to encounter.

Onwards and upwards in the direction of the radio masts on top of Turner’s Hill, we passed the remains of the old double-hedgerow which at one time formed part of a track leading all the way up to Rowley Church, about a mile away. Eventually, having reached the expanse of grassland adjacent to Portway Hill at the highest point of the site, where Lye Cross Colliery once dominated the landscape, and of which sadly, no trace remains today, we looked out at a mosaic of rank grassland and flowery meadow. Ever since the land was levelled and graded with spoil from the old colliery days little has changed other than Hawthorn becoming more dominant. The overgrown Hawthorn hedges marking the old field boundaries shelter the grassland from the brunt of the cold and drying easterly winds, and in doing so provide a certain amount of protection for the many butterflies, day-flying moths and other invertebrates found here. A search of the grassland here revealed Common Blue and Small Heath butterflies, and Mother Shipton and Burnet Companion moths.

To complete our circular walk, we headed back downhill, this time taking the track on the southern side of the site, passing close to the back gardens of houses in Kennford and Wadham Close, and following the wide track along the ridge of the water-stressed banks overlooking Wallace Road, to finally exit the site near to the Total garage on Birmingham New Road. As we descended a Holly Blue was seen and a Brimstone flew swiftly by. Last year small Alder Buckthorns were planted here, with the hope that once they have established Brimstones might breed here.

Today’s visit had been very rewarding with nine different butterflies recorded; Brimstone, Common Blue, Green Hairstreak, Green-veined White, Holly Blue, Small Copper, Small Heath, Small Tortoiseshell, Speckled Wood, and also the larvae of Orange-tip butterfly on the two main foodplants of this butterfly, Lady’s Smock and Hedge-garlic.

Several moths were also seen today, Angle Shades, Burnet Companion, Cinnabar, Mother Shipton, Small Magpie, and two micro-moths, Ruddy Streak, and Cranbus lathoniellis. Additionally, both larvae and their papery cocoons attached to grass stems of Narrow-bordered Five-spot Burnet and possibly Six-spot Burnet moths were seen in places.

As to be expected, many other invertebrates were also seen. Harlequin Ladybird, 7-spot ladybird, 14-spot ladybird, 16-spot Ladybird, 24-spot Ladybird, Violet Ground Beetle, Umbellifer Longhorn Beetle, Thick-legged Flower Beetle, Cardinal Beetle, Common Red-legged Robberfly, Batman Hoverfly, Grey-backed Snout-hoverfly, Thick-legged Hoverfly, Barred Ant-hill Hoverfly, Empis tessellata, Tipula luna, Dock Bug, Bishop’s Mitre Shieldbug, Hairy Shieldbug, Tawny Mining-bee, Ashy Mining-bee, Red-tailed Mining-bee, Honey Bee, Tree Bumblebee, Red-tailed Bumblebee, Common Carder Bee, Early Bumblebee, Buff-tailed Bumblebee, Orange-legged Furrow-bee, Buathra laborator, Yellow Meadow Ant, Azure Damselfly and Common Blue Damselfly.

Two new additions to the floral list for Portway Hill SINC were also made today, Spotted Medick Medicago arabica and Round-leaved Crane’s-bill Geranium rotundifolium.

 

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