The colony of house martins which nest on the water tower at the Estate Office entrance to Exbury Gardens is one of the largest in Hampshire. The nests are tucked up under the overhang of the roof on all four sides of the tower.
The martins usually arrive in April and set about repairing and re-building the (mud) nests. A few are always usurped by house sparrows, which take advantage of a ready-made cosy home; wisps of dried grass spilling from the hole or over the top of the cup give away the ones which have been stolen.
The nests are in all stages of repair; some are just broken fragments, some have gaping holes with half the mud sides gone, others are cup shaped, but the best are totally enclosed except for a circular entrance hole. Those which are occupied by sparrows usually have a larger entrance and are visibly lined or patched with grass.
The birds are at all stages of the nesting cycle: some are feeding young; you can see their heads poking out of the hole. The parents usually pay a swift visit and stuff something into the waiting gapes with hardly a pause. Blink and you miss it. Occasionally they enter the nests with the chicks, maybe for housekeeping purposes. At other nests you can see a sitting bird, and at still others birds are building or repairing their nests. These are likely to be young birds in their first season, practising the skills they will need for successful breeding.
The south side has the greatest number of active nests, with 18 this year. Three nests on this face contain sparrows, and four appear to be unoccupied. On the west side there are 14 occupied nests with no sparrows; the east side (facing the road) is the least popular, containing 9 occupied nests but no sparrows; the west has the most sparrows - with five stolen nests, two unoccupied, and 12 house martins. That all adds up to a total of 53 productive nests this year.