Some Notes on the local Meadow Brown Butterfly populations
Posted: Sun Nov 25, 2007 10:00 pm
Hello,
When researching the needs of butterflies, I went through each of the local
butterflies for their requirements of food plants and other needs.
The Meadow Brown Butterfly is ostensibly the one that would seem to be most
likely to be compatible with cattle grazing because its food plants are a
range of grasses.
On the downs near Shoreham we have four different habitats:
1) Mill Hill: original chalkhill on the lower slopes, ungrazed
2) Anchor Bottom: conservation grazing on chalk
3) Lancing Ring meadows on clay and chalk, forage harvested
4) Southwick Hill conservation grazing on clay and chalk
Method was by walking over the downs and counting the butterflies and
putting the reports on the web pages.
Summary,
In the summer the greatest concentrations of Meadow Browns occurred on the
meadows of Lancing Ring. These would be about double or more the number per
acre on Mill Hill and Anchor Bottom. Southwick Hill is not much good for any
butterflies.
This is not the whole story because in years where the Meadow Browns were
common, the numbers on Mill Hill per acre exceeded that of Anchor Botttom,
and the numbers on Mill Hill were usually higher, but not by an appreciable
amount.
This is not the whole story because the Meadow Browns in the south have an
autumn brood. For reasons not known to science why this occurs on the south
coast downs. Anyrate, the lower slopes of Mill Hill have this late brood,
but the other sites do not, or not any more than strays.
This is the state of the science. Most butterfly reports have observations
coupled with unproven hypotheses, some of which are wrong or not written
down very clearly.
Thtas about the state of play for most species.
Wildife meadows are better for the summer broods of Meadow Browns than
conservation pastures.
Chalkhill Blues are much interesting and Mill Hill is streets ahead of all
other sites locally. This is not entirely to do with Horseshoe Vetch, but
this plant is the essential factor. But the presence of Horseshoe Vetch does
not mean Chalkhill Blues. Horseshoe Vetch is present in large amounts on the
Slonk Hill Cutting but Chalkhill Blues are almost totally absent (one a year
recorded).
The other interesting study is Bird's Foot Trefoil and the Common Blue
Butterfly, but I will have to leave this for another message.
Adur Butterfly & Large Moth List
http://www.glaucus.org.uk/Butterfly-list2007.html
Cheers
Andy Horton
glaucus@...
Adur Valley Nature Notes
http://www.glaucus.org.uk/Adur2006.html
http://www.glaucus.org.uk/Adur2007.html
Adur Valley Nature Notes: November 2007
http://www.glaucus.org.uk/Nov2007.html
Adur Valley & Downs Gallery
http://www.flickr.com/groups/adur/pool/
When researching the needs of butterflies, I went through each of the local
butterflies for their requirements of food plants and other needs.
The Meadow Brown Butterfly is ostensibly the one that would seem to be most
likely to be compatible with cattle grazing because its food plants are a
range of grasses.
On the downs near Shoreham we have four different habitats:
1) Mill Hill: original chalkhill on the lower slopes, ungrazed
2) Anchor Bottom: conservation grazing on chalk
3) Lancing Ring meadows on clay and chalk, forage harvested
4) Southwick Hill conservation grazing on clay and chalk
Method was by walking over the downs and counting the butterflies and
putting the reports on the web pages.
Summary,
In the summer the greatest concentrations of Meadow Browns occurred on the
meadows of Lancing Ring. These would be about double or more the number per
acre on Mill Hill and Anchor Bottom. Southwick Hill is not much good for any
butterflies.
This is not the whole story because in years where the Meadow Browns were
common, the numbers on Mill Hill per acre exceeded that of Anchor Botttom,
and the numbers on Mill Hill were usually higher, but not by an appreciable
amount.
This is not the whole story because the Meadow Browns in the south have an
autumn brood. For reasons not known to science why this occurs on the south
coast downs. Anyrate, the lower slopes of Mill Hill have this late brood,
but the other sites do not, or not any more than strays.
This is the state of the science. Most butterfly reports have observations
coupled with unproven hypotheses, some of which are wrong or not written
down very clearly.
Thtas about the state of play for most species.
Wildife meadows are better for the summer broods of Meadow Browns than
conservation pastures.
Chalkhill Blues are much interesting and Mill Hill is streets ahead of all
other sites locally. This is not entirely to do with Horseshoe Vetch, but
this plant is the essential factor. But the presence of Horseshoe Vetch does
not mean Chalkhill Blues. Horseshoe Vetch is present in large amounts on the
Slonk Hill Cutting but Chalkhill Blues are almost totally absent (one a year
recorded).
The other interesting study is Bird's Foot Trefoil and the Common Blue
Butterfly, but I will have to leave this for another message.
Adur Butterfly & Large Moth List
http://www.glaucus.org.uk/Butterfly-list2007.html
Cheers
Andy Horton
glaucus@...
Adur Valley Nature Notes
http://www.glaucus.org.uk/Adur2006.html
http://www.glaucus.org.uk/Adur2007.html
Adur Valley Nature Notes: November 2007
http://www.glaucus.org.uk/Nov2007.html
Adur Valley & Downs Gallery
http://www.flickr.com/groups/adur/pool/