Tern Raft
One of the more important features of reservoirs that may impose constraints on the local wildlife is the variation in water levels that may occur. For some breeding birds this has been overcome by the use of floating platforms. Prior to the introduction of rafts no common terns had successfully bred at Alton.
We now consistently manage to ring around 50 young each year.In addition other bird species such as oyster catchers, coot and geese have also taken advantages of these safe and consistent breeding areas.Each raft is 10 feet square and is covered with shingle and a few larger stones for protection. Additional shelter is provided by timber shelves placed in the corners. A low fence is put around the raft to reduce the ability of other, more aggressive species such as geese, to push out the terns.
Tern Chick
Raft It is also important to provide secure anchorage and, to this effect, we have found that a single point attachment to a concrete weight by means of a polypropylene rope and short length of chain is more than adequate.Interestingly we have found that during the early part of the season the terns venture to the local Stour and Orwell estuaries to obtain the majority of the food with flounders forming a large part of their diet. It is not until late summer that the fry in the reservoir are big enough to constitute a worthwhile meal!