Saturday, February 23, 2019

Long-eared Owl Surveying - Late Winter / Early Spring


LEON aims to help raise awareness of UK & Irelands Long-eared Owls.


NB: Please feed in where ever you feel able, but remember to send your info to the relevant County Recorder / RBBP / BTO via the usual confidential channels.
BTO Birdtrack - Contact List for county-bird-recorders

Header image by Kevin Owens, Co.Durham.

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LEO SURVEYING
We have very little knowledge of Long-eared Owls over much of the country and going out to look & listen for Leo and submitting records to County Recorders (via existing regular channels) would greatly add to our baseline knowledge.

G.Ridley


 
Suggested Simple Survey Method: Late Winter / Spring
One of the most productive & simple means of locating Long-eared Owl pairs is a methodical approach at dusk. Late Winter / early Spring evening visits looking & listening for birds during calm conditions are a good way to confirm a presence that might otherwise be missed in days or weeks of dedicated daylight cold searching.

Find a sheltered vantage point approx. 50 metres from the leeward side of a copse or plantation, adjacent to open country. Get tucked in as the light starts to fade and simply wait. If you have no contacts from your position after the light has gone, move closer to treeline & listen again, move along the edge of the site stopping to listen again every 50 yards.

 
What to look & listen out for
Resident male Long-eared Owls will commence their late Winter moaning ‘song’ from New Year, and this will reach a peak as we progress through February.

S.Evans


March is a key month in the birds calendar, as pre-breeding activity increases in the half-light with bursts of ‘song’ accompanied by prominent wing-clapping display flights. The male will fly out around & above the likely nest site in a series of circuits in which he audibly taps his wing tips beneath his body. This reaches a peak during March, with pairs often becoming conspicuous in the half light around dusk, sometimes flying together, then becoming particularly vocal and animated during nest selection & mating, at the end of March / early April. In mature wood lots & shelterbelts the pair may indulge in a jig-jagging follow my leader display flight within the wood, up through the stems & canopy.

Males may ‘sing’ from anywhere within their territory and even in flight, but chiefly from the preferred nesting site. Here he will have a series of song perches, which can include the apex of a tree. Keep an eye on any obvious bare branches or isolated posts / saplings etc – birds will often fly out onto they before commencing with the evening’s activities. His singing, coupled with display flights can continue for hours, days & weeks, he will often break off to move out to hunt, bringing prey back to his mate often wing clapping to announce his arrival in the distance, she will pick up the tempo of her calling as he approaches.

The female tends to confine her activities close to the prospective natal area. NB: Her soft ‘paper & comb’ calling is the clincher when looking to confirm the location of a breeding pair. During nest selection the female may perch openly at or even on her chosen nest – repeated daylight visits at this stage can cause the pair to relocate. Different individuals react differently to an observer’s daytime presence. Although it is natural for Leo to adopt as sleek a profile as possible to help avoid detection, this mechanism tells us as observers that the owl will feel more secure if we were not there, or not as close – in contrast to this a particularly aggressive bird may well fly at or swoop round the observers head ! Having said that, dusk or evening visits are unlikely to affect the pairs activities once underway, provided the observer isn’t on top of the birds or making a commotion. Female Leos will contact call at night with some regularity from the nest, allowing the location to be pinned down without climbing trees.

Ultimately vocalisations & pre-breeding activity will depend upon when that particular season starts & how long it lasts (eg. Co.Durham 2017 – eggs were laid over a 12 week period )

D.Spiers
 
Where to look & listen
Leos will use any kind of arboreal habitat, but a good starting point is to select a location which you know or looks like it may hold Short-eared &/or Barn Owls.  This is likely to be an area of rough grassland, although Leos can be found in very many scenarios & habitat types including mixed farmland with field margins etc. Breeding Leos in the UK will utilise many habitat types from sea level up onto moorland sites at 500m provided there are old stick nests, or not as the case in some of the northern isles! Recently established community woodlands provide ideal hunting habitat, these new plantations are providing fresh opportunities for birds to exploit and will still be utilised long after the canopy has closed. The birds will hunt the exact same ground as the other two more conspicuous species but will be hidden away in any wood edge or copse which adjoins an area of rough grassland.  NB: Locations where Leos roost often also go on to provide nest sites.

 
Proximity of pairs
In peak vole years, during optimal conditions, breeding densities can be high with multiple pairs in close proximity. Single tetrads holding 6 pairs in Notts (D.Scott) and 8 pairs in Durham (S.Evans), with Scott also detailing 5 pairs in a single 1km square. Conversely, several pairs can appear to exist ‘in isolation’ – less productive ground resulting in far larger territories, some hunting 2.5km away from the nest, with these far roaming birds therefore being more difficult to locate & pin point…

 
What if I hear Tawny Owls ?
The relationship between local Leo & Tawny is often a complex one. Many examples exist of both species living and breeding in close proximity over several decades eg Notts, Lincs, Durham, Yorks. (D.Scott 1997, S.Evans unpublished, A.Jowett unpublished).  Do NOT be put off if you hear or see Tawnies – both species can tolerate one another, even in the same woodland block, whilst both using stick nests. Be aware that these two species may also rotate their presence/absence in a shelterbelt or wood.
Library image


 
Use of playback
It is not recommended to use any playback of recordings or tapes in the field other than to check/confirm your findings. Getting out in flat calm conditions will increase your chances of connecting with this species. A helpful tip is ‘cupped hand amplification’ – cupping your hands behind your ears really works to help amplify & help pin point any vocalisations.


 
Survey insights
In VC66, a County survey in 2005 saw just under half of all 41 surveyors see Leos, including 3 observing the species for the very first time – one fieldworker catching up with his ‘bogey bird’ after watching in the county for 20 years !  This area has radically reappraised its population with targeted fieldwork from many observers. 2019 will see groups out surveying for the species, including those from Wales & East Yorkshire.

Tony Fitches
Important Reminders
Please remember Long-eared Owl is a Schedule 1 species in Northern Ireland and the Isle of Man.

 
Here is the RSPB code of conduct for anyone new to birdwatching or surveying:  


 If you are fortunate enough to come across Leos this Spring there is a good chance that they may go on to breed – remember in most circumstances they will see you before you see them. If you do come across a bird in daylight, resist to temptation to get any closer, give them space, back off and hopefully you’ll have a whole season to enjoy watching them. Males can give a barking alarm call, females a curdling feline crying & both sexes ‘whick whack’ when alarmed or distressed.
 

Other resources
Xeno-canto Bird Calls resource:   https://www.xeno-canto.org/

Moon phase website:   https://moonphases.co.uk/

RBBP pages:  http://www.rbbp.org.uk/downloads/sp_guidelines_longeared_owl.pdf
BTO Birdfacts page: https://app.bto.org/birdfacts/results/bob7670.htm



RBBP have some guidance on the interpretation of behaviour to breeding evidence codes:
http://www.rbbp.org.uk/downloads/sp_guidelines_longeared_owl.pdf
 
 
PS: Please look after yourself ,especially If you are not accustomed to wandering around in the dark ! A small torch & a stout stick may be helpful. It may be prudent to let any landowners know your whereabouts - your activities & your vehicle may appear suspicious
 
Good Luck & heres hoping you have a positive experience.
 
LEON Team.
 

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