Blog post from Adam Fisher, PhD student, University of Liverpool and Research Intern, RSPB Centre for Conservation Science.
As part of my PhD programme I had the chance to take part in a three-month, fully-funded internship in a scientific role outside of my host institute. And it seemed like a great opportunity.
I started my PhD at the University of Liverpool in October 2015, studying the population-level effects of different mating behaviours in predatory invertebrates.
So far, I have used a mixture of lab work and computational biology to identify which mating behaviours are most likely to increase population extinction risk in a rapidly changing environment.
Why the RSPB?
Since I had no experience of doing research outside of an academic institute, I decided to look for an internship at a conservation charity.
A quick online search for UK conservation charities made it clear that the RSPB had a large and diverse conservation science department, so I got in-touch and began planning my internship.
My first contact with the RSPB was through Mark Eaton who suggested that I could spend three months analysing data for the 2019 State of Nature report. Upon arriving at the RSPB, I was introduced to Fiona Burns and Richard Gregory, who I would also be working with.
What was I doing?
The State of Nature report consolidates plant and animal data from over 50 UK conservation charities and provides a great opportunity to observe UK wildlife trends and identify areas of conservation concern. It would also give me a chance to improve on my statistical skills.
As part of the upcoming State of Nature report we plan to examine whether species-specific traits affect population trends. After a week or so of exchanging ideas about which traits to examine, we decided to look at whether specialism could predict population decline.
Numerous studies have shown that specialist species are more vulnerable to decline than generalists*, so this seemed like a promising avenue of research. We have analysed data from several groups of plants, insects and birds, and have generated some promising results; we are confident that the work will be suitable for publication.
Was my internship beneficial?
The internship was definitely worthwhile, it gave me experience working in an area of ecology I am not familiar with and has broadened my skill set. It was also great to spend some time with bird enthusiasts taking part in farmland bird counts and ringing. As a bonus, I have managed to exponentially increase the length of my bird list!
I would recommend doing a research internship to anyone who has the opportunity and wants to diversify their academic experience.
Adam’s Internship was funded by the Natural Environment Research Council as part of ACCE DTP programme.
Blog post by Toby Galligan, Senior Conservation Scientist, RSPB Centre for Conservation Science
SAVE’s major vulture telemetry project in Nepal is well underway. Seventeen free-ranging white-rumped vultures (Gyps bengalensis) fitted with satellite transmitters are providing us with valuable data on their movements and favourite locations. The 17 tracked birds comprise of 11 wild birds, plus the six released last year.
The project’s objective is twofold: to evaluate Nepal’s vulture conservation breeding and release programme; and to evaluate the safety of Nepal’s Vulture Safe Zone (VSZ).
The breeding programme is set to have its second good year for producing fledgling white-rumped vultures; and the VSZ is set to be the first region declared free from diclofenac and other NSAIDs toxic to vultures.
So far, the 17 vultures have clocked approximately nine vulture-years between them – that is, the combined time each vulture has been providing data in years. The first map shows movements and where they have been during this time*.
Map show the borders of Nepal and its districts. Districts in bright green are within the Vulture Safe Zone; whereas those in dark green are Diclofenac-free Districts. North of Nepal is the Tibetan Plateau of China; East and West of Nepal are the Himalayan Mountains of India and Bhutan; and South of Nepal is the Gangetic Plains of India.
Each dot is a location where a vulture was recorded. Different coloured dots represent different vultures.
The dots are clustered because the vultures tended to use the similar sites. Except for one vulture (light brown dots), which surprised us by travelling 900km west, along the edge of the Himalayan foothills, to beyond Shimla in Himachal Pradesh and back again.
This wild vulture was actually sighted in Uttarakhand at carcass dumps by the vulture team there (a great case of international collaboration in December, with BCN sending the coordinates and these being checked on the ground). And this shows what free-ranging vultures can do and why conservation actions need to happen across borders and vast areas.
But this vulture’s behaviour is unusual compared to the other vultures that were tagged.
The second map zooms in on the cluster of dots.
Closer inspection of the cluster reveals different vultures behaving differently.
For example, dark blue, red and dark brown spend considerable time in the hills; light purple has roamed west and spent considerable time in northern India; and light blue and yellow prefer to travel no further than the Lumbini vulture safe feeding site (South Nepal).
The white dots show the location of five of Nepal’s six Vulture Safe Feeding Sites; and the blue diamond (extreme right) shows the location of Nepal’s Vulture Conservation Breeding Centre.
Wild and captive vultures were all tagged and released at the Nawalparasi vulture safe feeding site - the white dot furthest to the right. Perhaps oddly, the vultures haven’t ventured far to the east of this site so far.
One key finding from this work (although perhaps not so surprising) is the number of locations of birds across the border in Uttar Pradesh (UP), India.
This has prompted some excellent transboundary linkages, with locations being visited by the BNHS/UP Forest Department teams, and discovering new feeding sites and potential breeding sites that were not previously known from the UP VSZ!
Within Nepal, the team discovered some new breeding colonies and important foraging sites while following these tagged vultures.
The third map zooms in on the Nawalparasi feeding site.
The feeding site is where the coloured dots are tightly clustered. Only the wild vultures are shown here.
The spread of coloured dots shows their movements to and from the feeding site. These vultures happily returned to the feeding site on several occasions despite having once been trapped and tagged nearby.
The fourth map is the same as the third, but shows the released vultures are shown instead of the wild vultures.
This is the six released vultures’ total movements since November 2017. None have so far moved more than 2km. With food being regularly supplied at the feeding site, these vultures don’t have any major impetus to range further away.
At least, this allows us to closely monitor them and we assume they will soon travel further.
Wild vultures are presently feeding chicks and relying on the regular food supply at this feedings site, but once the breeding season has ended we are considering temporarily stopping feeding to encourage the released vultures to explore more of the provisional Vulture Safe Zone.
The project is the collaborative effort of the Department of National Parks and Wildlife Conservation, Chitwan National Park, Bird Conservation Nepal, the RSPB, the International Centre of Birds of Prey, National Trust for Nature Conservation and the Zoological Society of London.
Save would like to thank BCN, RSPB, Krishna Bhusal & Toby Galligan for providing this exciting interim update. Also to Khima Balodi, to Corbett National Park staff, to Alka Dwivedi and Vibhu Prakash (BNHS) and especially to the BCN ground truthing team Devendra Chapaign, Ankit Bilash Joshi and Ishwari Chaudhary.
Blog post by Dr Ron Summers, Principal Conservation Scientist, RSPB Centre for Conservation Science.
Within northern Europe, common crossbills depend on Norway spruce seeds for food. The Norway spruce cone crop varies enormously between years and the variations are synchronous across a wide range. In years when no cones are produced, we see irruptions of crossbills to regions south of their normal range.
As Norway spruce isn’t native to the UK, previously irrupting common crossbills arriving from Fennoscandia and Russia could only forage on the tough woody cones of the native Scots pine. This was until the introduction of Norway spruce and Sitka spruce (a North American conifer) to enhance the national timber crop.
Now, Sitka spruce makes up half of the woodland area of Scotland, whilst Norway spruce comprises only three %. Sitka spruce in particular, has helped common crossbills become established in the UK as a breeding species.
A female common crossbill foraging on a Sitka spruce cone. Photo by Ron Summers
Why was I researching this?
While we were aware of the importance of spruces to crossbills, there was little known about their feeding habitats or indeed basic features of spruce cones on which they feed.
To understand this important part of these fascinating birds ecology, I measured cone sizes and seed fall, and collected spruce cones dropped by feeding crossbills to establish seed extraction efficiency. This research has recently been published in the journal Forestry.
Sitka spruce and Norway spruce cones differ in several respects. Norway spruce cones are much larger than Sitka cones. The latter are small enough for a crossbill to remove from the tree, hold against a stout branch with its foot, and pry apart scales with its crossed bills to extract the seeds. The cone is then discarded and tumbles to the ground.
However, crossbills are only able to do this for the smaller (lightest 10%) Norway spruce cones. The larger ones are too heavy, so the crossbills have to forage directly on these cones still attached to the tree.
Sitka spruce cones (above) and Norway spruce cones (below). The Sitka spruce cones are a mix of maturing (green/purple) and old cones (brown). Photos by Ron Summers.
What's the difference?
Another major difference between the two conifers is when they shed their seeds following the cones maturing in late summer. I studied this by catching seeds in plastic bins set under the canopy, with a muslin liner placed inside the bins catching the falling seeds.
Sitka spruce started shedding seed in autumn, thereby reducing the food supply for crossbills through autumn to spring, whereas Norway spruce retained their seeds until spring.
The early start to seed dispersal by Sitka spruce is a trait of many North American conifers. It is believed to be a strategy to reduce seed losses to pine squirrels, which begin removing and caching cones as soon as the cones have matured. In northern Europe, red squirrels don’t have the same caching tendency, so there has been no selective pressure on Norway spruce to disperse seed early.
To study seed extraction by crossbills on Sitka spruce cones, I had to search for foraging birds. When located, I approached the tree quietly, so that cones dropped by the birds could be observed as they fell, and then collected. I then dried the cones to extract and count remaining seeds.
I estimated the number of seeds in the cones (from cone length) before the crossbills started foraging, so by subtracting the number remaining, the number consumed was derived. The mean number of seeds taken from Sitka spruce cones was 87, and 68 from Norway spruces.
These were equivalent to 45% and 42% removed, respectively. There was a trend for fewer Sitka seeds to be taken across the period between autumn (August) and spring (March), coincident with fewer seeds being available as the seasons progressed.
Figure one: The seasonal decline in the number of seeds available (□) in Sitka spruce cones and numbers consumed in these cones (●) by common crossbills.
Incomplete extraction of seeds suggests that it is more profitable to switch to another cone to maximise average intake rate, and that the threshold for switching cones changes as the number of seeds declines.
Although optimal foraging may account for some of the variation in the number of Sitka spruce seeds taken, some of the low values may have been due to birds terminating feeding when disturbed, or when a flock decided to forage elsewhere.
Despite the seasonal decline in seed number, irregular cone production and the small seed size of Sitka spruce, this conifer is attractive to crossbills because the thin papery cone scales make it easy for crossbills to extract seeds.
This, plus its abundance in the UK, has clearly benefitted common crossbills, whose numbers exceeded 27,000 in the Scottish Highlands during 2008.
One conservation concern is that hybridisation with Scottish crossbills is now more likely when both crossbill species share other conifers, such as lodgepole pine, particularly in years when there are no Sitka spruce cones.
To date, cases of hybridisation have only been recorded between parrot and Scottish crossbills in Caledonian pinewoods.
It would probably be more difficult to detect hybridisation between Scottish and common crossbills, because it involves catching pairs of birds at nest sites, and these are more difficult to find in plantations, where the tree density is high.
The paper: 'Foraging patterns of common crossbills (Loxia curvirostra) on spruces (Picea spp.) in Scotland' has just been published in Forestry.