22 October 2013

Nest recording in 2013

We've been a bit late submitting our nest recording data for this year, but having finally sorted all the final outcome codes and monthly effort recording, I finally sent it all off to BTO this afternoon (see more on the BTO Nest Record Scheme here). The total of  144 nest records was pretty good, although admittedly a fair few of these were single-visit seabird records...

All our records of Great Black-backs and Cormorants are from Mullion Island
The top five species were Blue Tit (43), Cormorant (24), Shag (18), Great Black-backed Gull (16) and Barn Owl (12). Of these, where we had multiple visits at the right time of year, we found average clutch sizes of 7.2 for Blue Tit, 2.4 for Shag and 3.3 for Barn Owl (compared to 3.6 last year). Despite very low occupancy of Barn Owl sites this year, the average clutch size compared well to the 3.6 recorded last year, but the average brood size of 1.8 compared pretty badly to the 3.0 in 2012.

Also doing badly were Great Black-backed Gulls. On our first visit to Mullion Island we counted well over 100 chicks and eggs, but later visits (theoretically to colour-ring chicks) found only a handful of survivors, with perhaps as few as three or four birds fledging! What happened to the others is a worrying mystery.

Some of the mystery missing Great Black-back chicks
Conspicuous by its absence from the top five this year is Kittiwake. The Rinsey colony failed completely, with just six active nests all failing at the egg stage, which compares badly to the 44 active nests in 2012 (36% of which failed).

The full list of nest records submitted is below:

Blue Tit   43     Dipper  2  
Cormorant 24
Shag 18
Great Black-backed Gull     16
Barn Owl 12
Stock Dove      1
Herring Gull 9
Kittiwake 6
Tawny Owl1
Great Tit 6

Not one of mine, but this brood of Robins in a fertiliser bag
at the Lost Gardens of Heligan couldn't be left out

And perhaps not surprisingly, this nestbox in Lizard wasn't used...

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