Dutch Montagu’s harriers, new study

This video is about a young Montagu’s harrier, foraging in Lauwersmeer national park in the Netherlands.

From Ibis ornithological journal:


2nd November 2015

Enhancing food abundance and availability for harriers

Birdfields – a novel Agri-Environmental Scheme to improve foraging conditions for a vole-eating raptor

Almut Schlaich
Dutch Montagu’s Harrier Foundation & Conservation Ecology Group,
GELIFES (Groningen Institute for Evolutionary Life Sciences),
Groningen University, The Netherlands

Testing a novel agri-environment scheme based on the ecology of the target species, Montagu’s Harrier Circus pygargus
Schlaich, A.E., Klaassen, R.H.G., Bouten, W, Both, C & Koks, B.J. 2015. IBIS 157: 713-721. DOI: 10.1111/ibi.12299

The Montagu’s Harrier is a rare farmland breeding bird, not only in the UK, but also in the Netherlands where we have a small population of around 40 pairs. In the highly intensified agricultural landscape farmland birds struggle to find sufficient food to breed successfully. We tested a novel agri-environment scheme (AES) – coined Birdfields – to provide accessible food sources for breeding Montagu’s Harriers.

A small population of Montagu’s Harriers established in our study area in Eastern Groningen, the Netherlands, in the early 1990s when farmland was set aside on a large scale to counteract wheat overspill (Koks et al. 2007). The set-aside habitat was used for foraging, and the harriers nested in large wheat fields that characterize this intensively farmed area. After the set-aside regulation ended, the number of breeding pairs directly decreased again. To preserve Montagu’s Harriers for the Netherlands, agri-environment schemes (AES) like field margins and set-aside fields were introduced. This led to an increase in numbers and we nowadays have a population fluctuating around 40 breeding pairs (Figure 1).

In the Netherlands, Common Voles are the most important prey, which is exemplified by the fact that vole abundance determines breeding success and population growth (Koks et al. 2007). In order to understand where Montagu’s Harriers exactly find these prey in the intensively farmed landscape, and the exact role of AES in this, we tracked individual harriers using radio-transmitters and UvA-BiTS GPS-loggers. Surprisingly, the birds were not spending much time hunting on set-aside, but strongly preferred freshly mown grass fields (Trierweiler 2010, Klaassen et al. 2014). This seems paradoxical as vole abundance is much higher in set-aside habitats compared to other crops (Koks et al. 2007, Schlaich et al. 2015). The answer probably lies in the fact that prey are difficult to capture in dense set-aside vegetation. Thus, prey availability rather than prey abundance per se dictates habitat selection in foraging harriers.

Integrating knowledge on the Montagu’s Harrier ecology, we designed a novel AES – coined Birdfields – that aims at increasing both prey abundance and availability. Birdfields consist of alternating strips of set-aside and alfalfa (Figure 2). Set-aside strips are sown with a mixture of cereals, grasses and herbs, and their most important function is to enhance local densities of voles. Alfalfa strips are harvested three times per year, and their main function is to enhance prey availability. An additional advantage of growing alfalfa is that the harvest of alfalfa reduces the overall costs of the AES, making Birdfields a more economical alternative to current AES.

In 2011, two Birdfields were created close to a core breeding area of Montagu’s Harriers. These Birdfields were monitored in 2012-2013. During the same period, high-resolution tracking data of individual male Montagu’s Harriers was collected using UvA-BiTS GPS-loggers. With the help of volunteers vole abundance was monitored in set-aside and alfalfa strips, and small mammals killed during the mowing events were identified (Figure 3). This involved counting vole burrows in 6184 1m²-plots and walking 93.9 km behind the mowing machine! As expected, vole abundance was much higher in set-aside than in alfalfa, and nearly 90% of all observed small mammals were Common Voles. Detailed tracking data from four male Montagu’s Harriers in each season showed that birds used the Birdfields intensively during and after mowing events, in which the birds strongly preferred mown over unmown habitat (Figure 4).

Our results show that Birdfields form an efficient AES for Montagu’s Harriers as this novel measure not only enhances prey abundance but also prey accessibility. In addition, it is a more economic AES. Furthermore, many other species seem to profit from Birdfields in particular breeding Skylarks, breeding and wintering vole-eaters and wintering farmland birds. Consequently, the measure ‘Birdfields’ has now been officially implemented as a greening measure in the new Common Agricultural Policy (CAP) in Pillar 1 and Pillar 2 in The Netherlands. Meanwhile, the Ministry of Economic Affairs has started a country-wide pilot, executed by BirdLife Netherlands, Louis Bolk Instituut and the Dutch Montagu’s Harrier Foundation, to evaluate scientifically the general value of Birdfields for soil, insects, and farmland birds and already 230 ha of Birdfields have been implemented throughout the Netherlands. More than 300 ha will follow in 2016.

References and further reading

Klaassen, R. H. G., A. E. Schlaich, M. Franken, W. Bouten & B. J. Koks. 2014. GPS-loggers onthullen gedrag Grauwe kiekendieven in Oost-Groningse akkerland. De Levende Natuur 115:61-66.

Koks, B. J., C. Trierweiler, E. G. Visser, C. Dijkstra & J. Komdeur. 2007. Do voles make agricultural habitat attractive to Montagu’s Harrier Circus pygargus? Ibis 149:575-586.

Trierweiler, C. 2010. Travels to feed and food to breed. The annual cycle of a migratory raptor, Montagu´s harrier, in a modern world. PhD, University of Groningen, Groningen.

Scottish hen harriers tagged

This video is called [male] Hen Harrier (Circus cyaneus) sitting on the heath.

From Wildlife Extra:

Hen harriers tagged in new conservation project

Scottish hen harriers are being tracked via satellite tags so scientists can better understand the threats these rare birds face and identify the places they are most at risk.

The satellite tags transmit the locations of the harriers on a regular basis, and members of the public will be able to follow the movements of two individuals on a new website. For security reasons the information available online will be displayed with a two week delay.

Hen harriers used to be widespread in the British uplands but were pushed to the brink of extinction come 1900. Since then, numbers have slowly increased but there are still only around 505 breeding pairs in Scotland.

Bea Ayling, manager of the Hen Harrier LIFE+ Project, said: “Hen harriers suffered 20 per cent declines across Scotland between 2004 and 2010 and urgent action is needed to help conserve this species. Illegal killing by humans remains the main problem for these birds despite them having full legal protection for many years. This is because their usual diet of small birds and voles may also include red grouse, thus bringing them into conflict with gamekeepers. Several hen harriers have disappeared in recent months in northern England and one bird, named “Annie”, was found shot dead on moorland in south-west Scotland earlier this year.

“By fitting satellite tags to harriers we can track them accurately to see where they go and find out which areas they’re getting into trouble. We can also gain valuable information on breeding sites, nest locations and, should the worst happen, be able to locate and recover the bodies of dead harriers far more easily. The timely recovery of dead birds may also assist the police and prosecutors in bringing the perpetrators of crimes to justice.”

European kestrel nest video

This video shows an European kestrel nest.

Cees van Kempen from the Netherlands made the video.

European Montagu’s harriers migrating to Africa

This video shows a young Montagu’s harrier in Lauwersmeer national park im the Netherlands, on 2 August 2015.

Translated from the Dutch ornithologists of Werkgroep Grauwe Kiekendief:

Thursday, September 10th, 2015

The graceful silhouettes of Montagu’s harriers have become almost impossible to see in our country. Most have in fact begun their trek to the Sahel. Using satellite transmitters twelve Montagu’s harriers can be tracked on their journey.

On average, Montagu’s harriers travel some 5,000 kilometers to their wintering grounds. They do this in the fall at an average of 32 days. In spring, the migration takes about five days longer.

The birds which can be followed this season are Mark, Rowan, Roger and Rose from England, Astrid and Henry from Saxony-Anhalt [Germany], Geranda, Kees and Jürgen from Mecklenburg-Vorpommern [Germany] and Leen, Ludmila and Yura from Belarus. Ludmila was the first bird starting her migration, already on 1 August. Geranda was on September 9 still at her breeding grounds. Of the remaining harriers, some have already crossed over to Africa, but most are still in Europe.

Britain: Grouse shooting for ‘sport’ depends on intensive habitat management which damages protected wildlife sites, increases water pollution, increases flood risk, increases greenhouse gas emissions and too often leads to the illegal killing of protected wildlife such as Hen Harriers: petition here.

Peregrine falcon dustbath at Singapore building

This video is called Peregrine Falcon checking out a new condo, July 2015, Singapore.

From the Bird Ecology Study Group in Singapore about this:

In July 2015 Wong Weng Fai photographed a Peregrine Falcon (Falco peregrinus) having a dust-bath on the balcony floor of a yet to be completed apartment in a high-rise building.

Many birds keep their feathers in good condition by taking dust-bath LINK. They lie on the dusty ground and moves vigorously about to get the dirt particles onto their feathers. This helps to get rid of ectoparasites as well as stale secretions from their oil glands.

In the case of this falcon, it found a quiet spot in this uncompleted high-rise building.

The presence of sand particles as a result of building activities and the absence of workers in the unit made this an ideal site for its “bath’. It would not be long before the building would be completed and no opportunity for the peregrine to return. Maybe the photographer would then have an opportunity to document other birds taking shower baths?

Other methods of keeping their feathers in top condition include water bath LINK, preening LINK and anting LINK.

Cornell red-tailed hawk chicks have fledged

This video from the USa is called Cornell Hawks Highlights 2014.

From the Cornell Lab of Ornithology in the USA:

June 24, 2015

Up, up, and away…

One by one, the Cornell Hawks nestlings have departed the nest for their first flights. The oldest (nicknamed “F1”) took wing on June 21 and returned the next day to the platform. The youngest (F3) was the next to go, leaping from the platform at midday on June 22 after being harassed a bit by its remaining sibling. Not to be outdone, F2 departed the nest a few hours after F3, and now the young Red-tailed Hawks are busily exploring the nearby rooftops and treetops. Although Big Red and Ezra will continue to provide food and guidance for the fledgling hawks for another two months, the hawks will be seen on camera less as they range more widely.

Watch the Cam.

Hawk Chat Closing

With an empty nest now, the Cornell Hawks live chat is scheduled to wind down this coming Sunday, June 28, from 5:00 P.M. to 7:00 P.M. EDT. We’re looking forward to celebrating the season with another spectacular closing this year. Thanks to everyone for watching and sharing the experience!

Cornell young red-tailed hawks fledging?

This video from the USA is called Cornell Hawks 2015-Post-Hatch.

The Cornell Lab of Ornithology in the USA writes:

June 16, 2015

Here Today, Gone Tomorrow?

The hour is rapidly approaching when the young Cornell Hawks will take their first flight! If past years are any indication, one nestling will likely leave the nest in the next couple days, with its siblings soon to follow (click for an overview of the dates). Viewers have been on the edges of their seats during animated bouts of “wingercizing” and awkward near-falls as the young hawks explore ever closer to the platform’s edge. But between these bursts of activity you’re likely to see them still clustered together in the nest, watching the hours pass until their world widens.

Even after the hawks leave the nest, Big Red and Ezra will continue to look after them. Parents catch birds and small mammals to feed the youngsters for their first three weeks after fledging and may help supplement their youngsters’ diets for eight weeks or more while the young learn to hunt on their own. We’ll also share reports from our Birders-on-the-Ground (BOGs) who keep an eye out on campus as the young stray farther from the nest. During this time, the cam will stay active as our volunteer cam operators search for the young hawks amid the rooftops and lightposts of central Cornell campus.

Don’t miss out on the first flight! Join us for chat and share the excitement with the community. Watch the Cam.