Days & nights with Fern Owls

I’ve always had a fondness for Nightjars or to be more specific Caprimulgus europaeus.  It’s their evocative country names such as Fern Owl which offer insight from past naturalists about the haunts of these enigmatic birds?  If we accept that the term ‘fern’ probably equates to bracken and that their strange utterances might be considered owl-like in at least as far as they are generally heard in late evening then we can perhaps see why they were so named.  Additionally they are associated with areas where bracken occurs nearby to woodland habitat.

Here in the Humberhead Levels they are pretty much restricted to the peatlands with outlying areas of heathland occasionally attracting a few birds.  The population on Thorne & Hatfield Moors have had mixed fortunes over the decades.  In my youth it was not uncommon to flush birds from the tracks across the moors on regular basis but as the industrialisation of peat mining took its toll the population declined dramatically.  Fast forward and we are fortunate that the land is now public land and supporting good numbers of these fantastic birds.  The milling fields, once described by a local MP as resembling ‘battlefields’ is slowly but steadily being healed by nature with some assistance from European funding through a LIFE+ project.

Despite Fern Owls desirability as a birders ‘tick’ they are not easy to study and whilst there are many research projects from the southern heathlands and plantation clearances the Humberhead population is little studied.  Palmer (2000) was the last piece of statutory funded detailed research before that currently being undertaken in conjunction with the LIFE+ project.

One of the birds being studied was first ringed as an adult on Thorne Moors in 2013 so it’s doing well for a bird weighing less than 100gms.  Each May they return to breed and this study is being undertaken to assess the impact of the re-wetting of the peatlands upon the Special Protection Are (SPA) citation species (nightjar).  As the areas become wetter the birds which require dry ground may be displaced.  Where will they go?  Are there areas on site which have the potential to mitigate for this?

The intensity of the work has seen Lucy Ryan and her team spend extraordinary amounts of time in the field, and to their credit they could certainly not be described as ‘clock watchers’ or ‘nine to fives’.  Their dedication to the project has probably seen them suffer sleep deprivation as they clock up the hours in the short window that is the nightjars breeding season.  This project is scheduled to run for three years and saw a first year trial in 2015.  2017 is the penultimate season.

It has been a privilege to have spent time out there with them and to have such fantastic views of the birds in the hand.  It is rare to be able to gain this kind of access and it adds substance and understanding to the passion for these migrants who spend their breeding season with us.

It’s meant late nights and walking over punishing terrain, particularly with a damaged knee but these sessions have provided experiences which will last long in the memory.

Images above (copyright) show a male nightjar.  The white patches to wing tips and outer tail feathers are diagnostic.  The white patches on this bird’s outer tail feathers are particularly large.

Images above (copyright) show wing of female nightjar (no white spots) close up of head to show bristles and close of foot showing the comb on the nightjar’s middle toe.

Nightjars lay two eggs on bare ground without any material gathered to form any kind of nest. Nests have been found on bare ground with moss and leaf litter.  Some are in the shade of vegetation others in the open and exposed to the elements.

Images above (copyright) show eggs laid directly onto bare substrate. The chicks, thought to be about three days old still retain the egg tooth on the end of the bill (click on image to expand detail).  Interestingly, unlike many birds nightjars just leave the egg shells abandoned in situ after the young have hatched.

Images above (copyright) show a female nightjar about to be released after her vital statistics have been logged.  The two nestlings represent the future of the Humberhead population of this special bird?  Their cryptic camouflage hides them well but increased public access means that they are vulnerable to disturbance and displacement.  If a female is flushed from brooding young chicks they can die from exposure and cold.  Dogs off the lead running free, unknown to owners can maul chicks, so please help conserve these magical crepuscular Fern Owls by exercising care and caution when walking the moors.

Please note that this project is compliant with current legislation and has all the necessary authorisation, approval and licences required.  

Images, ALL copyright: H R Kirk

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