Elderly Shag strengthens our position in Europe!

Jim Lennon from the Shiants Auk Ringing Group writes:

Ringing seabirds can be mucky and challenging work, especially when you’re ducking under a rock to reach a Shag chick, while keeping an eye out for its protective parents (often the croaking male). However, this is soon forgotten when you receive news of one of them nearly 31 years later!

Shag chick 1227282 was one of a brood of three ringed on the Shiants Isles, Western Isles, on 30 June 1985 by Ms Sam Powell, a trainee ringer from South Wales working with the Shiants Auk Ringing Group. A total of 725 pulli from 377 broods was ringed on the Shiants that year.  Most of the subsequent recoveries were of birds that perished within the first 12 months, a few survived for four or five years and an exceptional bird was found dead after nine years.

But 1227282 outlived them all by a country mile.  For the next 30 years following ringing, it most likely spent its life breeding on the Shiants and in the waters of West Scotland, but we’ll never know for sure as it was never heard of again until John Taynton, a RSPB worker on the Shiants, found it freshly dead on 26 April 2016 i.e. a life span of 30 years 302 days.

According to the BTO’s latest longevity list (2014), this makes the Shiants bird the oldest ringed Shag in Britain & Ireland, and also in Europe (see Euring), raising the record by nearly a year.

Note:
The Euring information is not updated as regularly as the BTOs longevity lists because it needs to access all the data from all the Euring ringing schemes and this can take some time.  It currently indicates that a 34 yr old bird from the Shiants is Europe's oldest  Puffin but two just shy of 36 years old and one almost 37 years old, are listed on the BTO longevity records site.

Tawny having a tough time

The nests of Barn and Tawny Owl have been recorded in Lincolnshire and Nottinghamshire intensively since the mid 1980s. This has provided a wealth of information, which is used to look at many aspects of breeding success.

Adult Tawny Owl by Carol Greig

Adrian Blackburn and Jim Lennon, along with help from other ringers, checked 82 Tawny Owl nest boxes on 21-24 April 2013 in East Lincolnshire, and recorded an occupancy rate of just 17% (14 boxes). Squirrel, Jackdaw, Stock Dove and Great Tit were also recorded. In total in 2013, just 17 chicks were ringed from seven broods; half of these were provided by two surprisingly large broods of four chicks, with and one other containing three young while the remainder were the rest consisted of single nestlings or pairs of owlets. This is much lower than the average number of 36 ringed young recorded over the period 1996-2012 and far below the highest annual total ever, an impressive 62 chicks ringed in 2005.

There were still two nests with eggs on the last visit could potentially produce more chicks but are very unlikely too at this stage; the other five had failed either during incubation or soon after the chicks had hatched.  We posted previously about the hard time Barn Owls were having due to the cold spring, so finding that Tawny Owls were also having a hard time was not a great surprise.

Some reasonably healthy Tawny Owl chicks by Carol Greig

There is evidence of a lack of prey from the boxes with fewer voles and mice being found, these being replaced with more unusual items, including the hind leg of a hare, a Carrion Crow’s head and a few shrews. It is notable that the boxes in ‘prime’ deciduous woodland habitat, which usually produce the majority of offspring, fared worst, with those in suburban gardens achieving a much higher output. Could it be that small mammal populations in woods have become depleted during months of cold weather and poor vegetation growth, while garden rodent populations thrive on the artificial food provided for birds?  The situation is probably not helped by the breeding season for song birds being delayed by several weeks, potentially reducing the availability of young birds as prey.

Thanks to Adrian Blackburn and Jim Lennon for letting us know.

Kestrel vs Barn Owl - a nesting tale

The Barn Owl is by far the most commonly nest recorded owl species in the UK and Ireland (1,823 nest records in 2011, compared with 476 Tawny Owl and 143 Little Owl). The Barn Owl has benefited from all the hard work volunteers have put into increasing the number of possible nesting sites through Schedule 1 licenced nest box schemes all over the country. With the increase in nesting sites, Jackdaw, Stock Dove and Kestrel also nest in these boxes.

We have just heard from Adrian Blackburn concerning a Barn Owl box that has been used by Barn Owls for the last 3 years. When this box was checked on 05/06/2012 it had 5 white Barn Owl eggs and also 4 Kestrel eggs (below) that were being incubated by a female Barn Owl. This would normally mean that the owl had evicted the female Kestrel and laid her own. However when the next check was done, there were 5 tiny Barn Owl chicks and one tiny Kestrel chick, two warm Kestrel eggs and one addled Kestrel egg. The next box check had 3 Barn Owl chicks and the unhatched Kestrel egg.

As owls usually incubate from when the frst egg is laid, the owl chicks will hatch about a day apart, giving the earlier hatching chicks a better chance of survival during lean times. This is done by eating their siblings and in this case the smaller Kestrel chicks would probably be on the menu.

Adrian and his team have had dual occupation in their boxes before i.e. Barn Owl / Kestrel and Barn Owl / Stock Dove but never with a Barn Owl incubating the other species eggs and hatching them out!

Thanks to Jill Pakenham for the Barn Owl picture and Jim Lennon for the egg picture.