Thanks to Sam Crofts for this overview of the work he’s been doing with Little Owls in the county…
Being a keen birder and ringer when the opportunity to study Little Owls for my MSc thesis presented itself I jumped at the chance. Little Owls are a species exhibiting dramatic population declines of -57% in the U.K since 1994 and have been listed as a species of conservation concern in Europe. As the Little Owl was introduced to the U.K in the 1800s it is classified as an introduced breeder and therefore comparatively receives limited research and conservation attention compared with other species. A number of factors have been associated with the decline of Little Owls. Changes in land management practices, in particular agricultural intensification have led to the destruction of old orchards as well as removal of hedgerows and old growth trees that the owls use for nesting. The use of pesticides has also been suggested to reduce insect availability, a primary food source of the owls. Studies have investigated the habitat and diet of the Little Owl however the majority have focused on European populations and have not investigated the relationship between these two abiotic factors.
With the amazing enthusiasm of Gloucestershire Raptor Monitoring Group (GRMG) and multiple land owners I was able to conduct habitat surveys around nest sites and collect pellets to analyse habitat and diet. Phase 1 habitat surveys were conducted to classify parcels of land within a Little Owl territory according to vegetation composition. The height of vegetation was also recorded as it has been documented to influence hunting strategy. The remains of beetles and small mammals in pellets were identified to the species level where possible by Linda Losito and Bob Cowley. The data gathered was then combined to examine how habitat influences Little Owl diet.
The habitat surveys supported the findings of multiple studies from Europe suggesting that orchards and improved grasslands were the favoured habitat of UK little owls. A preference for short grazed grassland was also observed. However, territories contained a greater area of arable land on average when compared to reports from Europe. Analysis of habitat variation within the study sites revealed the majority of variation between sites could be accounted for by differing areas of improved grassland and arable. Using this information comparison of diet was then conducted between categories of sites defined by their habitat compositions. These categories were; sites dominated by improved grassland, sites with a large area of arable and sites with an intermediate mix of the two. In total beetle remains were identified into 43 categories, the majority of these being species however, in some cases it was only possible to attribute remains to a genus (Table 1).
There was no significant difference in either the quantity or number of insect species consumed between these categorisations of site habitat. There was however, a significant correlation between sites with a greater area of arable and increased consumption of small mammals, both in terms of quantity and number of species consumed. The height of vegetation within parcels of habitat was also quantified. When this data was compared with dietary information, a positive correlation was observed between the area of short grassland at a site and the quantity of beetles consumed. These results suggest a heterogeneous habitat dominated by short improved grassland, most probably grazed, alongside arable crops and old growth trees providing cavities for nesting are the most suitable for Little Owl territories. These findings add weight to suggestions that changes in land use could be driving Little Owl population decline. With widespread agricultural intensification heterogeneous landscapes are less common as was previously the case, potentially reducing the availability of optimal nesting sites and suitable hunting grounds.
Using the data gathered on habitat preferences in combination with land use data from the Centre for Ecology and Hydrology a model was produced to establish potential locations with suitable habitat for Little Owl nest sites in Gloucestershire. Suitable habitat was defined as areas dominated by improved grassland adjacent to smaller patches of arable. The locations of traditional orchards were also included as these provide excellent nesting opportunities. Areas close to main roads were also excluded, with a variety of exclusion distances being tested. This model was then validated against actual Little Owl sightings (figure 1). As can be seen the greatest concentration of traditional orchards and larger parcels of suitable habitat occur in the West of the county, it is also here that the greatest concentration of sightings occur. The more intensively farmed Cotswolds in the east have fewer orchards and smaller parcels of suitable land as well as fewer sightings of Little Owls. Statistical validation of the map and sightings revealed a correlation between predicted suitable habitat and actual Little Owl sightings.
Figure 12 Map of suitable Little Owl habitat within Gloucestershire. Minor roads buffer of 25 m and major roads (A, B and Motorways) buffered at 263.4. Reported Little Owl sightings included for validation of suitable habitat model.
Examination of pellets uncovered the alarming discovery of plastic items consumed by Little Owls. Items found ranged from short pieces of plastic binding to clothing tags. These pieces were found in pellets from sites closer to settlements demonstrating the damage our waste has on the environment.
A great deal of thanks is expressed to all those who assisted this project and the hope is that information gathered can assist the great work being undertaken by GRMG in conserving Little Owls in Gloucestershire.
Table 1. Beetle species list
July 25, 1984
The air is heavy and still. It needs a thunderstorm. We pass by some old derelict farmhouse outbuildings and cut across two fields going over barely negotiable stiles. The track narrows and Coppett Hill ridge closes hard against the river Wye at this point. A herd of deer make their presence felt and scrabble up the wooded hillside as we approach. The sun is coming up, mist on the slow moving river and all is perfectly still.
It is 1984 but could be 1784 here on this enchanted morning – with no sign of modern civilisation. As we move forward towards the impressive limestone Coldwell Cliffs the meadow widens and the oppressive becomes expansive. Here the Wye runs alongside the cliffs in a wide U shaped bend. It is now that Yat Rock and the cliffs loom high on the horizon, dominant, spectacular, powerful and majestic.
And now ‘kek kek kek kek kek‘ a guttural scream rents the air. The hairs stand out on the back of my neck. A shiver runs down my spine. An adult female Peregrine has launched from high on the face and attacks a much bigger Buzzard mercilessly. She repeatedly stoops and throws up, stoops and throws up, striking the hapless raptor with feathers a-flying.
This wild landscape is enhanced by the presence of the Peregrine. She adds a living dimension and makes these cliffs more wild, more spectacular, more menacing. I watched her with the tiercel and her four young till sundown and that day changed my life. I have been unashamedly in thrall to this unmatchable, wonderful raptor these last 30 years.
Down the years
Since that first day I have learnt all I can from the extensive literature and spent as much leisure time as possible watching Peregrines at Symonds Yat and elsewhere. To learn the ways of the Peregrine I have found that it is important to watch throughout the seasons, to follow their flights unstintingly and to take notes. Keep the ‘bins up when they’re in the air. Never give in to neck ache, shoulder ache or any other ache for that matter. Keep focussed. Then and only then will you be guaranteed to see the legendary hunting flights, the stoop,
the breath-taking flying manoeuvres that these perfectly adapted falcons are capable of.
After a few years behaviour patterns become discernible. One Peregrine’s habits and psychology can be discerned from another. Hunting technique can be rationalised and distinguished one bird from another. A change of resident territory owner can be inferred from changes in behaviour, habits, preferred perching locations as well as the physical characteristics of the bird itself.
Selected records from 1982 – 2017
My collated records now show that over the past 36 years five separate pairings have produced 91 young at an average rate of 2.53 per year. They have used 6 different eyrie sites on 2 separate rock faces over this period. In 1983 the eyrie was robbed and in 1984 the RSPB/ Forestry Commission started the Peregrine project. Since then there have been no losses to robbery.
In 1985 the sodden dead chicks were seen to be eaten by the adult. The female resident from 1982 – 1992 suffered a badly injured foot in 1985 which she carried for the rest of her life. It did not, however, appear to inhibit her hunting prowess.
In 1989 a Golden Eagle was observed from the viewpoint. Strange but true.
In 1993, 2005 and 2015 Barn Owls nested, apparently successfully, within 20 metres of the eyrie!
Since around 2005 we have also witnessed an increasing amount of Goshawk sightings from the viewpoint and this can make for some interesting interactions.
Even now, after thousands of hours of observation of many thousands of flights and hundreds of successful hunts, the thrill of watching Peregrines has never waned. It is always just like the first sighting. Captivating. Awe inspiring. Magical.
An update from Nat…
On Sunday 7th January I headed out for a morning in the field with GRMG’s very own Yoda; Rob – as well as a few others involved in local raptor/bird monitoring. We arrived for 11.00 and watched through until around 14.00 – prime time for watching raptors at this early time of year. Our focus was to monitor some Goshawks (Accipiter gentilis) and hopefully find a new nest to add to the many nests that the GRMG already monitor under Rob.
As we parked up and walked through the farm gate to follow the public footpath we had a pair of Common Buzzards (Buteo buteo) circling over the woodland behind us closely followed by a pair of Raven (Corvus corax); a good start. We didn’t stop to watch these as we would gain a better vantage point along the footpath and into the valley; stopping to observe at the top of an incline. The landscape was beautiful; rolling hills, fields of green and woodlands surrounding us, and it was a bright, clear and crisp morning.
The morning began with some incredible views of Raven with a couple of different pairs lightly displaying and flying in sync with one another over two of the visible woodlands – a positive start. From this you could clearly see the difference in Ravens compared to other corvids due to their much larger size as well as the difference in the male and female; the male being the larger bird.
Our monitoring session then went from success to success with encounters of Goshawks, Sparrowhawks (Accipiter nisus) and even Peregrine Falcons (Falco peregrinus). Our focus was on one area of woodland in the distance (where we haven’t yet pinned down the breeding Goshawk pair) as well as the woodland both in front of us and behind us where Rob has previously found the nests and need monitoring. On around three occasions we had courtship displays of Goshawks over our known territories and on one occasion Rob spotted a lone Goshawk flying out of some tall trees in the woodland we were focusing on – it flew past us and over the line of a ridge of trees next to us. This will now be followed up with a visit to that woodland and the near area where the bird left in order to look for a nest – or indeed the start of a new one.
One thing that can be difficult to determine in the field and from some distance is which species you are in fact looking at – especially if they are for example both a species of hawk. Goshawks and Sparrowhawks are very similar in shape but yet differ greatly in size. On this occasion, we had an interaction between Goshawk and Sparrowhawk which was astounding and made it very clear to differentiate between the two species. Unfortunately, you do not always see both together to make this differentiation clear, so an easier way to separate the two is by looking at the head – Goshawks have a longer head projection compared with Sparrowhawks. Sparrowhawks also often tend to resemble more of a ‘T’ shape in flight too.
At one point, far in the distance, I caught a glimpse of two raptors interacting with one another and they soon headed our way. The birds in view were two female Sparrowhawks – with one probably chasing off the other. We were amazed at how quickly they travelled over our way as we watched them and observed this interesting behaviour.
All of these birds we monitor are very agile on the wing – even the Raven. On one occasion a pair of Ravens worked together to chase off their local Goshawk and as they were circling they both were much more able than the Goshawk in these particular conditions to gain the advantage of height. Their intelligence was also very apparent during this interaction – with the pair working together to move the Goshawk on.
For me raptor monitoring is still very new and was all started by the Peregrine Falcon – so this session was made even more memorable with two Peregrines overhead. The local Goshawks, however, did not like having the Peregrines around which made for even more fantastic interactions between different species with the Goshawk doing everything it could to move the Peregrines on.
If any of you attended our Field ID last year with Rob, you will know that if the conditions are right and you are patient then you will see displaying Raptors and hopefully go on to locate their nests. Look for courtship behaviour early on in the season and where the birds fly out from and drop down in to. Around 13.30 the Goshawks had gone quiet and the Buzzards then started to begin hovering in the wind and circling on the thermals and we decided to end our session for the day. It was clear from today that our local raptors, especially the earlier breeders (Raven and then Goshawk) are indeed already becoming territorial for the upcoming season and re-establishing their pair bonds ready to breed in the coming months. My local Peregrine pair are also both defending their territory already. We are already looking forward to the upcoming season, and as ever we have a lot to do.
GRMG are pleased to announce our next hosted talk. This is a ticketed event as usual, but on this occasion, tickets are FREE OF CHARGE.
Guy Shorrock will be giving his talk “On the trail of Raptor Killers”. Guy has worked for the RSPB’s Investigations Team for 26 years and is one of their senior officers. A former Greater Manchester Police Officer, he has investigated a wide variety of bird-related crime, from egg collecting to the selling of wild Goshawks for falconry – and much much more. He has also helped NGOs abroad in places like Malta and Cyprus.
The talk is on Wednesday 22nd November, beginning at 7.30pm, and will take place at Ribston Hall High School, Stroud Road, Gloucester, GL1 5LE.
To ensure your place, follow this link to claim your free ticket.
Peregrine Falcons are fantastic birds and we are lucky in this county to be able to see them sometimes at close quarters.
Cheltenham and Gloucester both have pairs right in the city and they can be seen easily. Those birds are used to disturbance because life just goes on around them; I have also been lucky enough to see a pair of Peregrines in a recycling centre with thousands of people going within maybe 50 metres of the birds and them not caring at all! But those birds have chosen to nest there, so they know its a busy place.
Some of our Peregrines in Gloucestershire nest in disused quarries which might only have relatively few people visiting, maybe a hundred people over a year and certainly not tens of thousands. They have not been exposed to disturbance and so are more sensitive. We all want people to enjoy these birds and also photograph them if they have the opportunity but there are times when it can really put the young birds at risk or affect the success of a nest.
Early on in the year if the birds are disturbed constantly they just won’t nest there, and once the birds make what is called a scrape (the pair will try to craft a small bowl in the ground to allow for the nest to nestle there) they are protected by law.
The law that protects Peregrines is called the Wildlife and Countryside Act 1981 which actually covers all nesting birds but certain other birds are afforded more protection and this list is called Schedule One. The birds are protected under law until they have fully fledged and not dependent on the nest.
Last year several individuals were given Conditional Discharges after admitting disturbance of Peregrines at a site in Gloucestershire.
This year an appeal is going to go out shortly to identify someone potentially disturbing another Peregrine site. We have also had reports of photographers taking pictures of females sat on their nest, very young chicks and adults flying around the photographer’s head. All these would be classed as disturbance in law, but more importantly, you are risking the success of the parents raising their young.
We certainly don’t want to discourage people from watching these birds especially if they are looking out for new sites and report their sightings to us. Photos of colour rings are very useful, and you can act as and as well our eyes and ears’ looking out for people that may be wanting to harm the birds. But we would like you to think carefully before visiting sites at sensitive times, not getting too close and especially being careful with birds that are not used to the daily hustle and bustle of a city, certainly not to disturb them whilst sitting on eggs or with young that have not yet fledged. Thank you!
If you do see anything suspicious involving wild birds of prey in Gloucestershire, please report it to our telephone hotline 07960 047016 and to the police – see our post of May 5th.
Our spring 2017 newsletter has been sent out to subscribers. In this issue we have an update on wildlife crime in the county, information on sightings and surveys, a guest article about Ravens this breeding season and information about our exciting Goshawk colour-ringing project. You can download a copy here and previous issues can be downloaded from our documents page.