In search of an elusive Hairstreak, Satyrium pruni
Mar 1, 2015 13:22:20 GMT
deliasfanatic, mygos, and 5 more like this
Post by nomad on Mar 1, 2015 13:22:20 GMT
The Black Hairstreak, Satyrium pruni is a rare and local butterfly in Britain that occurs in a few Midland counties. This hairstreak is an elusive species that usually flies only in the canopy, where in warm weather it will feed on the honeydew. Only very occasionally will this butterfly descend to feed on woodland flowers, usually those of the sweet smelling Privet (Ligustrum vulgare). In the afternoon, if you are very lucky you may encounter an egg-laying female. Although this small butterfly appears black in flight, because of the plain upperside, S. pruni like many hairstreak species will only rest or feed with the wings closed. The undersides have an very attractive underside pattern.
My favourite place to look for this hairstreak, is on the edge of a large Oxfordshire forest where the foodplant blackthorn, Prunus spinosa is plentiful. The hedgerows here have tall ashes and oaks where the butterflies spent much of their time in the canopy, only rarely popping down to the Privet flowers when honey dew is scarce in its lofty habitat, such as after a period of heavy rain.
The forest is still an excellent place for butterflies, but once this area had many more species. Those butterflies that were once found here have disappeared from many British woodlands due to changes in the management of them and the extensive planting of conifers.
Arriving in the woodland, it was a pleasant but a mainly cloudy day with periods of warm sunshine. It's quite a long walk through the woodland to the S. pruni site, so I usually arrive by bicycle. There are other areas where the butterfly has been seen in the forest, but although I have searched there, they have eluded me. Reaching the site, I enter through a deer gate. The area was fenced to protect the sloe bushes against the ravages of the deer and this worked fine for the first few years, but the animals pushed under the fences by streams and I have seen three species of deer during my latest visits. Today, there is a browsing line of up to 4 feet on the sloe bushes all around the meadow. There used to be a large colony of another elusive and beautiful hairstreak, Thecla betulae, but because the females of this species lay low down on the blackthorn, the population has been decimated here. It will be interesting to see if the even rarer S. pruni dwindle in future years.
A bicycle can be very useful for exploring a large area.
The deer browsing line on the Blackthorn bushes (Prunus spinosa ) at this site left, the foodplant of two rare hairstreaks Satyrium pruni and Thecla betulae.
Today I was early, I hid my bicycle, walked through dense woodland and went through the prickly sloe tunnel to arrive in the meadow. The long grass was very wet and I was soon soaked up to my knees. Searching for Black Hairstreaks low down is literally like looking for a needle in a haystack. Extreme patience is required, those that like to arrive and find there butterfly quickly may have no luck with this species. I have been here when fellow entomologists has turned up, camera in hand, done a quick circuit of the hedges and drawn a blank, they often then leave within the hour disappointed. I had a look at a large clump of Privet bushes that grew up into the blackthorn, only the bees seemed to be present, but only I could only view a fraction of the flowers. The sun appeared and Marbled Whites, Melanargia galathea and Meadow Browns , Maniola jurtina flew lazily among the grass. It was three hours before I saw my first S. pruni with the aid of binoculars, probably two males chasing each other at breath neck speed across the top of Ash trees. There were other sightings but none were descending. I walked around the sloe bushes until at the far end of the meadow, I came across a sheltered spot, enclosed by two Oaks and tall Blackthorns where the Privet grew up though brambles.
Then on the highest Privet spray , I noticed a S. pruni was feeding, but well out of reach of my camera. The butterfly was disturbed by a bee and jinked off up into the trees. It was now three o' clock in the afternoon. It was hot here, and there was the constant hum of flies and bees. Then a pristine S. pruni appeared out of nowhere, these insects can fly at an amazing speed and are hard to follow with the eye. I edged closer, held my breath, and I took a few images. Then the butterfly was gone, a Red Admiral, Vanessa atalanta had arrived close by, sending the much smaller insect spiralling up into the canopy.
Feeding female of Satyrium pruni.
On another visit, I searched all day with no luck, the day was hot and there was only brief glimpes of Black Hairstreaks high in the Ashes. I was about to leave, when I noticed a man and a women had arrived. " Had I seen any S. pruni " , they asked, no I replied, they looked very disappointed. The women then exclaimed " is that one ", pointing to a sloe bush and there inches away was a pristine egg-laying female!!
The egg-laying female S. pruni.
S. pruni. Male bottom.
The pleasant sweet smelling Wild Roses (Rubus species) were being visited by the Longhorn Beetle, Stenocorus meridianus.
My favourite place to look for this hairstreak, is on the edge of a large Oxfordshire forest where the foodplant blackthorn, Prunus spinosa is plentiful. The hedgerows here have tall ashes and oaks where the butterflies spent much of their time in the canopy, only rarely popping down to the Privet flowers when honey dew is scarce in its lofty habitat, such as after a period of heavy rain.
The forest is still an excellent place for butterflies, but once this area had many more species. Those butterflies that were once found here have disappeared from many British woodlands due to changes in the management of them and the extensive planting of conifers.
Arriving in the woodland, it was a pleasant but a mainly cloudy day with periods of warm sunshine. It's quite a long walk through the woodland to the S. pruni site, so I usually arrive by bicycle. There are other areas where the butterfly has been seen in the forest, but although I have searched there, they have eluded me. Reaching the site, I enter through a deer gate. The area was fenced to protect the sloe bushes against the ravages of the deer and this worked fine for the first few years, but the animals pushed under the fences by streams and I have seen three species of deer during my latest visits. Today, there is a browsing line of up to 4 feet on the sloe bushes all around the meadow. There used to be a large colony of another elusive and beautiful hairstreak, Thecla betulae, but because the females of this species lay low down on the blackthorn, the population has been decimated here. It will be interesting to see if the even rarer S. pruni dwindle in future years.
A bicycle can be very useful for exploring a large area.
The deer browsing line on the Blackthorn bushes (Prunus spinosa ) at this site left, the foodplant of two rare hairstreaks Satyrium pruni and Thecla betulae.
Today I was early, I hid my bicycle, walked through dense woodland and went through the prickly sloe tunnel to arrive in the meadow. The long grass was very wet and I was soon soaked up to my knees. Searching for Black Hairstreaks low down is literally like looking for a needle in a haystack. Extreme patience is required, those that like to arrive and find there butterfly quickly may have no luck with this species. I have been here when fellow entomologists has turned up, camera in hand, done a quick circuit of the hedges and drawn a blank, they often then leave within the hour disappointed. I had a look at a large clump of Privet bushes that grew up into the blackthorn, only the bees seemed to be present, but only I could only view a fraction of the flowers. The sun appeared and Marbled Whites, Melanargia galathea and Meadow Browns , Maniola jurtina flew lazily among the grass. It was three hours before I saw my first S. pruni with the aid of binoculars, probably two males chasing each other at breath neck speed across the top of Ash trees. There were other sightings but none were descending. I walked around the sloe bushes until at the far end of the meadow, I came across a sheltered spot, enclosed by two Oaks and tall Blackthorns where the Privet grew up though brambles.
Then on the highest Privet spray , I noticed a S. pruni was feeding, but well out of reach of my camera. The butterfly was disturbed by a bee and jinked off up into the trees. It was now three o' clock in the afternoon. It was hot here, and there was the constant hum of flies and bees. Then a pristine S. pruni appeared out of nowhere, these insects can fly at an amazing speed and are hard to follow with the eye. I edged closer, held my breath, and I took a few images. Then the butterfly was gone, a Red Admiral, Vanessa atalanta had arrived close by, sending the much smaller insect spiralling up into the canopy.
Feeding female of Satyrium pruni.
On another visit, I searched all day with no luck, the day was hot and there was only brief glimpes of Black Hairstreaks high in the Ashes. I was about to leave, when I noticed a man and a women had arrived. " Had I seen any S. pruni " , they asked, no I replied, they looked very disappointed. The women then exclaimed " is that one ", pointing to a sloe bush and there inches away was a pristine egg-laying female!!
The egg-laying female S. pruni.
S. pruni. Male bottom.
The pleasant sweet smelling Wild Roses (Rubus species) were being visited by the Longhorn Beetle, Stenocorus meridianus.