Houmet Paradis, Bordeaux

19 June 2014

Chris Mourant and I met at 05.30 for an early morning monitoring visit to the small islet of Houmet Paradis off Bordeaux. This is the first time I’ve included this islet in the annual seabird monitoring…and the first discovery of the morning was what a mistake this has been!

Given its small size, it is surprising that Houmet Paradis is such a haven for nesting gulls and Oystercatchers. Approaching the islet from the causeway it was immediately obvious that many gulls were breeding there this year. In fact the area is now one main grassy islet, with three adjacent tiny rocky areas. Not too long ago this would have all been a single island, but erosion has created the present landscape.

All parts of the coastal areas of the islet contained nesting gulls. A rough estimate for nests observed and agitated adult birds overhead was in the region of 70-80 pairs of Herring Gulls and at least three pairs of Great Black-backed Gulls. This is more than we would have expected for the islet.

Most of the nests recorded had hatched chicks, with a full range from three quarters fledged to only a few days old. Only two GBBG chicks were found, but there must have been more present that were too good at hiding! We rapidly completed circuits around all the pinnacles of rock and main islet, colour ringing 22 Herring Gull chicks in the process. There were at least another 15-20 chicks that were currently too small to ring.

Also on the positive side was the presence of at least five pairs of Oystercatchers – again a high density for the area of rock/grass. The high number of nesting seabirds on Houmet Paradis is a real contrast to what we have seen on the northern islet of Omptolle over the past couple of seasons. On this islet the presence of Brown Rats appears in recent years to have resulted in almost zero breeding success and very few nesting gulls now. The two islets are a stark contrast to each other!

However…it is not all good news at Houmet Paradis. Careful observation by Chris and me revealed quite a few dead small gull chicks (15+) and several nests of eggs that had clearly been predated by Brown Rats. It is clear that these invasive non-native predators have now reached Houmet Paradis and are feeding on the nesting seabirds. European Rabbit is also present on the main islet, but this is seen as an advantage in keeping the vegetation down and creating a burrow system, which can also be used by seabirds.

Conclusion

With a breeding population of 70-80 pairs of Herring Gulls, three plus pairs of GBBGs and 5-6 pairs of Oystercatchers, Houmet Paradis is a small, but very valuable gem in the Bailiwick’s seabird crown. La Société’s Seabird Monitoring Team believes that the island also has good potential for nesting European Storm Petrel (and perhaps even Little Egrets)…but only if the problem of rat predation can be swiftly addressed.

 Recommendations:-

1.       A programme to seriously reduce (or eliminate) Brown Rats from Houmet Paradis and Omptolle should be progressed as soon as possible; and

2.       The islet should receive similar protection from human disturbance as Omptolle to the north in that it should be closed for access between 01 March and 31 July each year, with appropriate signage erected on the Bordeaux car park side of the Causeway to inform people before they cross the low water causeway to reach the islands. It is clear from the nesting activity this year that the islets are presently not often disturbed by visitors, so there should be little public resistance to this very justifiable and time-restricted closure.

 

 

PKV

 

19 June 2014