The Breeding Ecology of the Lapwing at Seal Sands, Teesside:: with reference to Food, the Environment and three Neighbouring Species.

Abstract

The breeding success of the Lapwing at the ICI Brinefields, Teesside, was studied in comparison to three other species - the Ringed Plover, Redshank and Skylark. Environmental data was recorded and pitfall traps were set up to study the available food. Clutch losses were low in comparison with other studies for all four species, there being no significant difference between species. Predation accounted for most losses. Growth rates of chicks varied widely between species. Lapwing chicks grew slowly - at a rate significantly lower than a study in Teesdale this year. Ringed Plover chicks grew slowly too, though at a slightly faster and more steady rate. The growth of the Skylark chicks was quick and unrestricted. Differences in growth rates were probably attributable to differences in the availability of food to the species. Many Lapwing chicks grew up by channel edges where their food was, although relatively easy to find, not very abundant. Dry weather and saline water may have caused the chicks to dehydrate. Brooding of Lapwing chicks was shown to decrease with age and be extremely rare in direct sunlight. Lapwing chick mortality was very high - there being a calculated zero survival rate. Ringed Plovers faired much better, (54% of chicks fledging); Skylark chicks had even better survival rates. Predation was not thought to be the major cause of the Lapwing's low survival rate - partially because of the high survival of other species and partially because of the low clutch predation rate. The mortality of Lapwing chicks was positively correlated to their growth rates and this suggested that poor growth and the problems of dehydration were probably the major causes of mortality.