Thursday 14 March 2013, by
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The LPO Anjou is the partner in charge of actions in the Basses Vallées Angevines – contact.
The LPO Anjou aims at "protecting birds and the ecosystems on which they depend and, in particular, the associated flora and fauna" and overall biodiversity. Created in 1991, the LPO Anjou developed from the Groupe Angevin d’Etudes Ornithologiques established in 1976. It had 1 200 members in 2010 and has 3 priority areas for action :
- updating knowledge on the conservation status of wildlife (birds, bats, beavers ...),
- implementing programmes for endangered species and for high-value habitats,
- education and raising public awareness about environmental issues.
The LPO Anjou and conservation
The LPO Anjou currently manages 408 ha of wetland purchased by the national LPO in the Basses Vallées Angevines (within the ACE / ACNAT / LIFE programmes), manages bat caves, hills and dry grasslands, and also a regional nature reserve. It is an associated operator on the Natura 2000 site “Basses Vallées Angevines” and is also involved in the Loire Valley and in the development and implementation of management plans (called Documents d’Objectifs) on these sites.
The LPO Anjou and the Corncrake
Since the early 1980s, the Corncrake population in the Basses Vallées Angevines has been regularly monitored. Night counts of calling males provide knowledge about the evolution of populations.
Thanks to agri-environmental measures (OGAF, OLAE) implemented in the survey area in the early 1990s, the Corncrake population had recovered to 400 calling males by the end of the 20th century. In 2000 and 2001, however, late floods (May-June, in some locations July) produced such widespread destruction that only a quarter of the population remained.
A slow recovery to previous numbers has been noted, confirming that the species may re-colonize the site if it remains favourable for breeding.
**Ringing calling males
In 1995, a first attempt was madeto capture calling males by day : one single bird was captured. Between 1996 and 2000, only seven calling males were ringed by this method.
Fortunately, British researchers have published a new technique for capture: the capture of males must take place at night, from April to July. Birds are identified when calling and captured with a dip net whose edges are protected to avoid injuring the birds.
Using this method, 560 males were captured in seven years on the BVA, allowing several re-captures of ringed birds.
The capture zone was extended in 2002 to the whole of France : the objective is to detect possible movements between breeding sites of the species. The programme, approved by the CRBPO (Research Centre for ringing bird populations), is coordinated by Matthieu Vaslin and Franck Noël.
**Monitoring of mowing procedures
Monitoring mowing is a major operation, which involves 3 or 4 people continuously from 20 June to 10 August. Each monitoring programme includes the collection of a variety of data: speed of the mower, manner of mowing (friendly mowing, centre outwards, or strips), number of sighted birds ...
When mowing has been completed, a careful examination of the area is carried out to find the bodies of birds unable to escape.
During the monitoring process, the moulting adults and fledgings are caught for ringing. Biometric measurements (weight, length of the wing, beak and tarsus ...) are carried out on each bird. Birds are then released a short distance away, in an uncut field.
From 1995 to 2007, 338 young were ringed, and 37 moulting adults. Towards the end of July 2003, a moulting male was captured during mowing monitoring. It was a calling male which had been ringed two months previously, two miles away. In July 2005, two males which had been ringed in spring were recovered.
Introduced from 2000 to 2002, this monitoring gives information about the movement of chicks after mowing. Birds are ringed and equipped with a transmitter attached to their backs. Their movements are monitored daily until loss of the transmitter signal.
Initial results indicate that the birds move significant distances after mowing, presumably in taking an escape route to reach a refuge area. In June 2000, a bird equipped with a transmitter just after mowing was sadly killed a few hours later by a mower in the grass where it took refuge...
Because of lack of funds for the purchase of transmitters, monitoring could unfortunately not be continued.
**Diet and food availability
During spring and summer 2000, 13 traps were located throughout the BVA, in different habitats located in flood plains : hayfields, poplar, hedgerows,…. The results are currently being analyzed. The areas furnishing the bulk of the biomass consumed by Corncrakes (small invertebrates) are hayfields which are flooded for long periods.
Orthoptera inventories were conducted and densities calculated by the establishment of grids of one meter square : some plots held up to 530 000 Orthoptera/ha.
In addition, the gizzards of Corncrakes found dead after mowing were collected and analyzed to establish the diversity of prey consumed. In 2001, these analyses have progressively expanded to other sites in that 7 gizzards from Champagne-Ardenne, 3 from Normandy and one from Spain were examined.
All results will be published shortly and subsequently posted on this page.