The early spring of 2018 will be remembered for an unseasonably cold snap at the end of February, “the Beast from the East” and this was followed by more cold weather in late March and into April. Bad weather early in the season can affect the breeding success of some species due to females perhaps being in poorer condition which in turn means they lay fewer eggs, so how did the cold weather affect kites during the later breeding season?
Well in the end, the summer turned out to be one of the warmest and driest on record, with very few heavy rain events or high winds, and altogether 171 breeding attempts were monitored. The results indicate that the cold snap early on actually had little or no lingering impacts;
|Monitoring 2018||Average 1994-2017|
|% Nests Successful||71.9%||62.5%|
|Fledged per Nest||0.94||0.90|
|Fledged per Successful Nest||1.31||1.41|
The number of young fledged per breeding attempt (0.94) is slightly higher than average, and the percentage of breeding attempts that were successful (71.9%) is the highest ever recorded, with the average from 1994 to 2017 being 62.5%.
With Welsh kites, lower nest survival is inevitably associated with bad weather, and the higher figure for 2018 is almost certainly due to the exceptionally warm dry weather during the 2018 main breeding season, resulting in ideal foraging conditions and less risk of exposure to wet and windy weather which is known to increase nestling mortality.
The slightly higher nest productivity in 2018 is due to a higher proportion of successful nests, rather than larger broods, as the mean productivity per successful pair (1.31) is lower than the long-term average of 1.41. It is predicted that brood size will begin to show a decrease as the population approaches its carrying capacity and competition for food limits productivity.