BOCN News

   top story:  
 
Owl Tower News Update 2017 - view live camera

Story dated: 5/27/2016

Since reporting on the original story in May 2016, we are very pleased to report that the barn owl pair has taken up residence again in the tower following brief appearances by the adult male in February and early March.

Go to: http://www.lenpicktrust.org.uk/owl-project/4593449091 to view live camera and diary updates

A brief history

Since the first purpose-made owl tower was built in 2000 and the publication of our owl tower advisory leaflet for farmers, developers and local authorities in 2006, many more towers have been constructed, both by way of mitigation for development sites and purely for reasons of conservation. Most of the towers that have been built since that time have attracted breeding barn owls and some are shared with kestrels.

With the help of Bob Sheppard, Barn Owl Conservation Network Adviser in Lincolnshire, The Len Pick Trust has built two owl towers, the latest being completed in autumn 2015. Five barn owl chicks were ringed in the first owl tower in 2014 and a pair of barn owls took up residence and laid eggs in the most recently-built tower in 2016. Sadly the nesting attempt was unsuccessful and it is hoped the pair will raise young in 2017.

The owl tower leaflet is available in pdf format – please email bocnenquiries@aol.com for a copy.

Colin Shawyer Barn Owl Conservation Network Founder and Co-ordinator

 
     
   other news:  
 
2016 – an unusual year

Story dated: 11/30/2016

An unusually mixed year
In many parts of the UK this has been a particularly mixed year with early breeding for some pairs, which surprisingly resulted in complete or partial clutch failure, and small brood sizes for those that were successful. In spite of the relatively high vole abundance at the beginning of the year, the unusually inclement weather in mid-late April was probably to blame, making it difficult for males to provide food. This in turn forced their partners to vacate nests, causing incubation to be interrupted and eggs and recently hatched young to chill and to die. During nest monitoring at some sites, therefore, we came across deserted whole clutches and unhatched eggs. At other nest sites that had been occupied earlier, the complete absence of eggs or young, suggested that they had been eaten and to the untrained eye, offered little evidence that breeding had been attempted.

Second broods
However, many of the successful early breeders which had already laid full clutches by mid-April, followed up with second clutches in early July, most of which were significantly larger than the ‘firsts’, some nests producing seven, eight and occasionally nine young to fledging. Even those pairs which failed completely on early clutches, repeated in June, again producing larger than average clutches and larger than average, brood sizes. Although, in most years, the fledging success of second broods is especially low this was quite the opposite at many sites in 2016. This success was undoubtedly assisted by the increasingly high vole numbers coupled with the unusually warm and especially dry weather conditions throughout the autumn months of August, September and October.

Late breeding
A proportion of other barn owls in Britain which laid later in May and others which didn’t start breeding until late June, were able to produce 3-5 young to fledging. This achieved a higher fledging success than the owls which laid early in late March and April but lower than that produced from most second broods.

East versus West
As I predicted before the season began, barn owls in the central and western regions of Britain experienced more nest failures, lower brood sizes and far fewer second broods than eastern regions, the converse of what was experienced in 2015 and which I reported on at the end of last year.

Overall breeding success
In spite of the low brood sizes in early 2016 I suspect we will, nevertheless, record a relatively high number of barn owls ringed in Britain this year, particularly in the eastern half of England. This will be buoyed-up by the success of both late and second broods, culminating overall in a significantly higher than average fledging success.

Winter thoughts
When I published the results of the Barn Owl Survey of Britain and Ireland in 1987 I was able to show that over 80% of nest sites in Britain occurred at low altitudes, below 100 m asl with only 10% below 150 m. Even in counties like Lincolnshire noted for its low-lying topography, breeding barn owls were absent from the Lincolnshire Wolds which barely rise above 140 m asl. This understanding was reflected in the conservation strategy that was subsequently developed, largely to focus our long-term UK conservation works to low-lying lands. This strategy has served us in the BOCN well, with the breeding population now, as we know, 2-3 times higher than it was three decades ago.

After the survey was completed in 1985, however, winters in Britain became much milder allowing barn owls the opportunity of occupying ground above these altitudes and to breed in what had previously been no-go areas for this bird. Not unexpectedly, however, it is the owls in these marginal areas that are the first to suffer during harsh winters, since snowfall and more importantly the days than snow persists on the ground, increases significantly with altitude.

If the forthcoming winter proves to be harsher than usual, which is what some forecasters are suggesting, we can expect the loss of those barn owls which have either chosen to occupy lands above 150 m or, in more recent years, have extended their range into the more northerly latitudes of Britain. Consequently, adult losses on quite a considerable scale, were last evidenced in these marginal ‘upland’ areas during a severe spell of winter snowfall in February and March 2013 and even now, three years later, a significant number of these breeding sites remain vacant.

What then for 2017?
I am finding it unusually hard to predict what we might expect for the barn owl season in 2017. Nevertheless, I think there will be a slow start to the breeding season especially for those pairs which double-brooded in eastern England this year. I would, however, expect the high vole abundance seen in 2016 to be maintained during the early half of next year. This should be reflected by high levels of occupancy at traditional barn owl nest sites, a late-April laying date for most pairs and a slightly higher than average brood sizes in most regions. And should second broods occur anywhere in 2017 I would expect these to be confined to central and western regions of Britain.

Colin Shawyer
Barn Owl Conservation Network Co-ordinator – UK and Ireland
November 2016
Email: colinshawyer@aol.com

The Barn Owl is specially protected under Schedule 1 of the Wildlife and Countryside Act, making it unlawful to intentionally or recklessly disturb it whilst it is preparing to nest or is at the nest with eggs or young, or to disturb its dependent young. Schedule 1 Disturbance Licences are issued to experienced barn owl fieldworkers by the British Trust for Ornithology or by Natural England, Natural Resources Wales, Northern Ireland Environment Agency and Scottish Natural Heritage.


 
     
   other news:  
 
This Season's Update
Story dated: 4/15/2016

Early nest visits Yesterday (13th April) nest visits to a sample of fifteen barn owl nest sites in one of our main study areas in eastern England indicated that nest occupancy was high with pairs present at most sites.

All of the adult females were at or well above 365g, below which breeding cannot usually occur. Average weights were closer to 400g and the appearance of developing brood patches in all but one bird indicated that egg-laying whilst not imminent, would probably begin between the last few days of April and first few days of May. A more developed brood patch on one individual indicated that this bird is likely to begin laying in the next few days and for a few occasional pairs in England this was reported to have occurred in the first week of April.

Male weights, like those of their partners, were also high at about 350g. All this indicates that field voles (the main prey of the barn owl) have since the beginnings of their resurgence in July/August last year, now achieved a sufficiently high abundance to stimulate successful breeding in most barn owls this year. It is likely that during the year vole numbers will continue to increase and by 2017 achieve peak levels in much of the UK.

Nest visits this year As most of you on the BOCN know, I have undertaken this sampling exercise every year since the 1990’s. The purpose of this is to assist nest recorders and ringers to plan their visits to barn owl sites safely at the appropriate time. As most experienced barn owl recorders know nest visits prior to egg-laying in March/April can result in nest abandonment for a significant number of pairs. A similar level of sensitivity remains until the full clutch has been laid, particularly at those sites occupied for the first time and by owls that are breeding for the first time.

Using an ‘includer’ to cap the entrance of the nestbox significantly reduces disturbance to breeding barn owls at this time of the year. In particular it prevents them from flying out of the nestbox and allows us to replace them carefully after their biometrics have been taken. For example, of the 15 occupied nestboxes checked yesterday none of the adults attempted to vacate their breeding site after the includer had been removed.

Optimising nest inspection I would estimate that in the UK about three-quarters of barn owls will begin laying eggs in 15-20 days time. This means that my colleagues and I will make no further visits until after full clutches have been laid. However, the majority of our nest inspections in England will begin during the third or fourth week of June.

I hope that this information will be useful to my BOCN and BTO colleagues and allow us to optimise the timing of our barn owl nest visits this year.

Best wishes for what should be a reasonably good breeding season in 2016 and one which will most certainly be far better than last year. Keep in touch

Colin Shawyer
Barn Owl Conservation Network Co-ordinator – UK and Ireland
14th April 2016
Email: colinshawyer@aol.com

The Barn Owl is specially protected under Schedule 1 of the Wildlife and Countryside Act, making it unlawful to intentionally or recklessly disturb it whilst it is preparing to nest or is at the nest with eggs or young, or to disturb its dependent young. Schedule 1 Disturbance Licences are issued to experienced barn owl fieldworkers by the British Trust for Ornithology or by Natural England, Natural Resources Wales, Northern Ireland Environment Agency and Scottish Natural Heritage.


 
     
   search the news archive:  
 
keyword(s) :
 
 
 
contacts | acknowledgements | copyright 
 
 
    Search the site: