13 January 2015

2015 nesting season underway by New Year!

Dave Leech writes:

For many BTO nest recorders, particularly those monitoring Barn Owl repeat breeding attempts well into the late autumn, it feels like the 2014 breeding season has only just drawn to a close. However, the respite is brief – while we seek shelter from the biting winter gales, the avian community is gearing up for the coming spring.

The Met Office have recently announced that 2014 was the warmest year on record in the UK and this winter has certainly been mild if, as most bird ringers will point out, a tad windy. Mild weather at the start of the year can certainly stimulate opportunistic singing, and I’ve already heard Great Tit, Wren and Dunnock in song within walking distance of my house in southwest Norfolk; nest recorder Mark Lawrence has been listening to the reedy warbling of the latter since early December on his patch in Devon.

Dunnock singing - Liz Cutting

While the nestling diet of these birds is not necessarily conducive to early breeding, species able to take advantage of soil invertebrates are less limited by food availability and may breed opportunistically at the end of winter, particularly around human habitation where temperatures are artificially raised and bird feeders provide additional sustenance. Nest recorder Mark Lucas has already reported his first clutch of Robin eggs in North Yorkshire via Twitter, found on the 9th January, beating the earliest record submitted to the BTO Nest Record Scheme by a fortnight. A pair of Mistle Thrush breeding in a Glasgow park were also flagged up on Twitter, the young having fledged in the last week.

Mistle Thrush nest - Herbert and Howells

Some birds couldn’t even wait for the New Year to start the 2015 season. RSPB warden Doug Radford was told of a Moorhen on eggs in Cambridgeshire in mid-December which had hatched by Christmas, and we’ve also received reports of Grey Heron laying at the start of the month. Not to be outdone, the BTO’s own Nick Moran stumbled across a brood of small Mallard ducklings on the 12th December at our reserve in Norfolk.

Mallard with ducklings - John Harding

While these examples demonstrate birds ability to respond to windows of opportunity, they are all anomalies. The data collected by BTO volunteers for the Nest Record Scheme over the past 75 years tells us that the main Robin breeding season kicks off towards the end of March, while most Moorhens start to lay from the beginning of April onwards.  Grey Herons are early breeders (Table 1), but laying doesn’t typically start until mid-February, with Raven generally the next species to follow in any number, then Tawny Owl, Collared Dove and Magpie at the very beginning of March.

BTO data have played a key role in demonstrating the advance in avian laying dates in response to the warming climate, as summarised in the recent BirdTrends report, and it is vital to ensure that this monitoring is ongoing. So, if you’re looking for a New Year’s resolution that furthers your knowledge while also giving something back to the conservation effort, why not make 2015 your first year as a nest recorder?

Table 1. Top 10 earliest UK breeders as calculated using Nest Record Scheme data for the period 2000-2009. Dates shown are the fifth percentile of the laying date distribution. Note that some early breeding species (e.g. Long-eared Owl, Crossbill) are excluded due to very small sample sizes.

1 comment:

  1. Singing Males-North Devon
    Mistle Thrush 16/1/15
    Wood Pigeon 17/1/15
    Dipper 18/1/15
    Song Thrush 19/1/15