Monthly Archives: November 2017

Chough report: October 2017

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A few of the Jersey choughs signalling dinner time. Photo by Liz Corry.

By Liz Corry

As October drew to a close it was achingly apparent that the chough flock was down from 38 to 36 individuals. The two wild-hatched females who went missing in September had still not made an appearance, forcing us to reluctantly record them as missing presumed dead.

This is the first time we have lost wild-hatched birds post-fledging period. One can’t help feel a sense of responsibility. These individuals were known to have a nematode infection, but attempts to medicate them had failed before they went missing. All we can do now is monitor the remaining choughs to ensure the same fate doesn’t befall them.

So we did, and guess what…two of the adults started sneezing. Egg and Helier began with the ‘I’m not sneezing, just clearing my nostrils’ subtle sneeze. After a few days Egg stopped whereas Helier continued and progressively worsened.

After a few failed catch ups due to jammed hatches, intelligent corvids, and of all things Portuguese forest fires (see ‘Sepia skies’ below) Helier was finally locked in the aviary allowing her to be treated by the vet team. She was released back into the wild straight after her worming injection and appears to be much improved.

Nematodes are part of the natural ecosystem. Choughs feeding in the wild will be exposed to them and have to tolerate or succumb. This year is turning out to be the worst since the project began in terms of number of infected birds and fatalities warranting further investigation.

Sepia skies

Having worked at Sorel for several years now you would have thought that everything that could go wrong in a catch up had done or at least been theorised and accounted for. Hinges sticking on trap doors, birds not showing up or not hungry enough to want to go inside, mountain bikers zooming past scaring the flock into the air, etcetera. Not once had we thought to account for Caribbean hurricanes and Portuguese forest fires!

On the morning of the first planned attempt to catch up Helier the skies in Jersey, and parts of the UK, were looking very ominous. Walking around Sorel it felt like someone had put a sepia filter on the world. Frustratingly my camera phone kept adding its own filter so the photos below don’t fully set the scene.

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On 16th October 2017 the skies above Jersey turned a sepia colour. Photo by Liz Corry.

Low cloud filled the skies throughout the morning. Around lunchtime the sun made an appearance, but looked more like Mars than our beloved sun. There were no horsemen on the horizon so instead of embracing impending doom I turned to the Gods of Google.

A red sun breaking out from the cloud of dust and ash in the atmosphere. Photo by Liz Corry.

An explanation for the near apocalyptic conditions was provided by the BBC. Remnants of Hurricane Ophelia passing over the south of England and Channel Islands were dragging dust from the Sahara and smoke from the devastating forest fires in Portugal and Spain across our skies.

I tried explaining this to a very confused flock of choughs who were clearly conflicted about what time they should go to roost. One might think this would be advantageous to someone trying to lock birds in an aviary. Nope. Instead it meant they just sat and stared at me in their perplexed state. A twenty-minute stand-off resulted in a dejected keeper walking away left to come up with a Plan B.

Roost check

Plan B failed. In fact it wasn’t until Plan E was executed that we were able to lock the sick chough in the aviary. The new plan arose from the need to know who was roosting in the aviary in case we had to lock in the sick bird for longer than a day. There was a small chance she roosted in the aviary already rather than the quarry. If so, all we had to do was wait until the birds had gone to roost and quietly shut the external hatches.

Cut to the scene of a person in dark clothes vaulting a field gate at night only lit by the stars and the dim headlights from a teenager’s car (one assumes from the discarded firework packaging and soda cans found the next morning) idling at Sorel Point.

The operation provided extra information other than Helier’s roosting site. A total of twelve choughs were roosting inside the aviary including Dusty the very first wild-hatched chough and the two females who follow him.

Kevin and Bean were hanging around outside the aviary. They could have used one of the external roost spaces at the aviary or simply flown over from the quarry at first light to forage nearby. The other interesting find was the kestrel who shot out of the external roost box when I arrived in the morning to check on the choughs.

There are no photos from Operation If this doesn’t work we’re screwed. So instead here are a couple taken at Les Landes when checking for signs of choughs at sunset.

A view of the Pinacle at sunset. Photo by Liz Corry

Sunset at Les Landes. Photo by Liz Corry.

The Women’s Institute expedition to the north coast

Earlier in the year the ladies of La Moye WI had invited me to give a talk about the choughs. Several of their members were already aware of the project, but had not realised that the historic breeding sites for Jersey choughs were in fact along the coastline at La Moye.

Enthusiasm for the project continued to grow as the evening went on, fuelled by the obligatory tea and cake, and by the end of the night a trip to Sorel was penned in the diary.

After a few clashes in the calendar a small group from La Moye finally made it up to the north coast this month. Glyn walked them around the conservation fields and release site. Not all of the choughs were present, but certainly enough to make an impact and demonstrate their amazing flying skills. I sadly missed out as I was in England, but from the looks on their faces I think they enjoyed it.

La moye WI (1)

 

Does the early bird catch the caterpillar?

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Willow warbler (6). Photo by Mick DrydenFrom BTO Science

The time that birds decide to breed has a strong impact upon the likely success of raising their young to independence. Pairs of birds will generally time egg laying to maximise the availability of food for their chicks. However, one of the strongest impacts of climate change so far has been to alter the timing of spring. In response to milder temperatures, flowers and insects are all appearing earlier than they used to. Songbirds struggling to match their timing to the changing climate could be facing population declines.

To test this, BTO, in collaboration with The Woodland Trust, Rothamsted Research, Butterfly Conservation and the Centre for Ecology and Hydrology (CEH), have collated some of the most comprehensive long-term data on the timing of spring from across the UK. They have related changes in the timing of leaf and flower emergence as well as aphid, butterfly and moth emergence, to changes in the timing of egg-laying, tracked by the BTO/JNCC Nest Record Scheme. Survey data from 1983 to 2010 was used to estimate variation in spring phenology from 280 plant and insect species and the egg-laying phenology of 21 British songbird species to explore the effects on avian population trends and potential underlying demographic mechanisms.

Common whitethroat (2). Photo by Mick Dryden

As expected, in warmer springs, birds do tend to breed late relative to the timing of spring. However, by using data from the BTO/JNCC ringing scheme to monitor changes in the number of fledglings produced by each species per year, the study’s authors found no evidence that these mismatched species were also suffering a long-term decline in breeding success. This suggests that the population declines observed in many British songbirds are not directly caused by the effect of mismatch on breeding success.

These results significantly increase our understanding of the impacts of climate change upon birds by showing there is not a strong link between changes in the timing of spring and long-term trends in breeding success. The heroic efforts of thousands of volunteers recording information on birds, insects and plants were vital in providing the long-term data required to understand the impacts of climate change upon bird populations, and we thank them for their hard work and dedication.

See the paper The sensitivity of breeding songbirds to change in seasonal timing is linked to population change but cannot be directly attributed to the effects of trophic asynchrony on productivity here

Plémont – how to create species rich grassland…. or heathland

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Plemont headlandBy Jon Parkes 

July 2016 saw the official opening of Plémont Headland and for the first time in over 140 years (before the original “Plémont Hotel” was built in 1874) the public have been free to enjoy this special place.

Creating and protecting “green space” for people has been at the heart of the Plémont debate and acquisition and indeed forms a very important part of the National Trust for Jersey’s ethos. But ensuring that nature has a home is also a vital component of what we do and there has never been a time when action has been so desperately needed.

In 2015 The States Department of the Environment published the results of the Jersey Butterfly Monitoring Scheme after 10 years of collecting data across 38 sites by a team of dedicated volunteers. The results suggest that whilst Jersey’s butterflies might be faring slightly better to those in the UK, the surveyed population has still decreased by 14%, (compared to 29% in the UK). Interestingly Jersey’s butterfly population is doing best in semi-natural sites as opposed to those in agricultural or urban habitats where they are declining. In fact the green hairstreak is one species that is doing particularly well and has been recorded as increasing by 458% in the last 10 years as opposed to suffering a 40% decrease in the UK. This could be seen as a strong indication of the importance of managed semi-natural sites such as Plémont.

Ponds

The creation of two ponds at Plémont was eagerly anticipated by the local toad and palmate newt population, who were literally queuing up to jump in upon their completion. For two consecutive years the Eastern Pond has been used by both species to breed. This year, the larger Western Pond has seen a whole new generation of toadlets emerge after metamorphosing from their tadpole stage.

Common toad. Photo by Kristian Bell

Despite the amphibian successes, both ponds have experienced teething problems and most noticeably the appearance of the lime-green algal blooms. Spirogyra is a family of around 400 species of filamentous algae that is commonly found in freshwater and is indicative of clean water that has high concentrations of phosphates and nitrates. It can be easily removed but doing so would jeopardise any invertebrate life or tadpoles that would become encapsulated amongst the tiny strands of algae.

Plemont pond

Another issue the ponds face is loss of water through evaporation, due to their exposed position to the sun, wind and transpiration – the evaporation of water from plant leaves. Whilst there is means to top up the water levels from a well, this would mean the introduction of more nutrients which would cause more algae. The proposed solution is to encourage more oxygenating plants and remove the algae once the toads have emerged from the water, decreasing the level of nutrients over time. Equilibrium will be reached, the water quality will improve and we will have to accept that the water levels will drop in the summer months. As long as there is water during the amphibians’ breeding period (February-June) the pond is serving its purpose and will act much like many natural ponds without constant water inflow.

Reseda luteola Weld R

Grassland

Back in the spring of 2015 you may remember the huge mounds of sandy soil which were spread over the footprint of the demolished buildings. Over 7,000 tonnes of sandy soil, sourced from Les Quennevais and recycled soil from La Collette formed the base of what we now refer to as the restoration area. To create a heathland such as Les Landes we would need a free draining sandy soil with a low pH (pH 5-6 ideally) and low nutrient levels. It is easier to maintain a species-rich wild flower habitat when there are fewer nutrients in the soil. If you add fertiliser (or compost or a lot of manure) to the soil, a small number of competitive plants are able to rapidly exploit these extra nutrients. These species then tend to become dominant and other plants are less able to compete for space. Most plants rely on a relationship with fungi and soil micro-organisms in order to grow. Fertilisers have a negative impact on these organisms making it more difficult for the flowers to grow.  With very little choice available, in the quantities we would need, a mixture of sandy soil, sourced from Les Quennevais and recycled sand from La Collette was chosen. Although the average pH was around 8.5, the particularly low nutrient status would mean far less of a burden when it would come to managing the developing vegetation.

Plemont headland 5

Snow bunting, Plemont, November 2017. Photo by Romano da Costa

This June our Conservation Officer, Jon Rault, assisted by the very knowledgeable local botanist Anne Haden, undertook a vegetation survey to assess how things have developed and have some interesting results. Around 50 plant species have so far been recorded including: wild carrot, toad rush, birds-foot-trefoil and small-flowered catchfly. Maritime Duneland plants such as fragrant evening-primrose, sea beet and sea radish have appeared, but this isn’t so surprising considering the origins of the soil, Les Quennevais of course being built on Dunes. Some more invasive plants such as the non-native cape cudweed and spotted medick which may need some management have become quite well established and some more exotic species including echium and Californian poppy have appeared as likely remnants of the holiday camp era.

Lotus corniculatis Common Bird's-foot-trefoil

Oneothera sricta. Fragrant Evening Primrose.Resent soil tests have confirmed that pH levels are still rather alkaline at between pH 8.5 and 8.9 and this is unlikely to change without any intervention due to the amount of concrete based material that must be underneath the layer of imported calcareous sand. Perhaps more encouraging is the nutrient status results from the same soil samples. For example, the amount of available phosphorus is currently between 8.8 and 25.8 mg/l with a “P index” of 0-3, compared to a recently tested former agricultural field which showed levels of available phosphorus at between 66.2 and 153.4mg/l giving a “P index” of between 4 and 7.

Beta vulgaris subsp maritima Sea Beet.Our current situation, with the encouraging results of vegetation surveys, indicates that the soil choice was a good one. Whilst our soil pH is much higher than we would have ideally liked, this is something that can be changed by adding sulphur, an expensive but affective way of raising acidity. As the results from the former agricultural field’s shows, high soil fertility is much more of a problem with no “magic cure”.

The decision on whether to try to acidify our soil in the effort to meet our original vision of creating a heathland is not one that needs to be made straight away and whilst wildlife and people are clearly making good use of the site, we have already achieved much of what we wanted to do.

For the meanwhile, the addition of calcareous grassland to our north coast may be something of an oddity but this may also be its strength and reason to remain as such. A new and interesting patch adding heterogeneity to the landscape is something that’s often lacking.

Further decisions will be required but there will be a need to balance and create opportunities for nature as well as public access and enjoyment.

This piece was originally published in the National Trust for Jersey magazine Discover and is reprinted here with kind permission

Choughs at Sorel Point May 2017. Photo by Mark Sleep

 

Tribute In Light: A chance to study light’s dramatic impact on bird migration

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Tribute in Light, New York City. By Glyn Lowe - Flickr, CC BY 2.0, https://commons.wikimedia.org/w/index.php?curid=28138731From The Cornell Lab of Ornithology: All About Birds

Billions of birds undertake migratory journeys each spring and autumn. Most of these spectacular movements go unseen, occurring under the cover of darkness. A new study provides some of the most compelling evidence yet that artificial light at night causes radical changes in the behaviour of migrating birds.

“We found that migrating birds gather in large numbers because they’re attracted to the light,” says Benjamin Van Doren of Oxford University, a lead author of the study. “They slow down, start circling, and call more frequently. They end up burning energy without making any progress and risk colliding with nearby buildings or being caught by predators.”

Scientists from the University of Oxford, the Cornell Lab of Ornithology, and New York City Audubon studied migrant bird behaviour over seven years in a truly unique setting—Tribute in Light in New York City, held to commemorate the September 11, 2001, terrorist attack. Two beams of light–each with 44 xenon bulbs of 7,000 watts—rise into the night sky, mirroring the twin towers of the World Trade Center where nearly 3,000 lives were lost.

“This was a rare opportunity to witness the impact of powerful ground-based lights on nocturnally migrating birds,” says co-lead author Kyle Horton, Cornell Lab, but working at the University of Oklahoma during the study. “This analysis would not have been possible without the help of tribute organizers.”

Well before the results of the study highlighted the effects of the installation, New York City Audubon reached out to the original tribute organizers, the Municipal Art Society, to let them know about the impacts of artificial light on migratory birds. In 2002, the two organisations developed a protocol to save the affected birds. The tribute lights are turned off for approximately 20 minutes when more than 1,000 birds are seen circling in the beams or flying dangerously low with frequent calling. The National September 11 Memorial & Museum, which took over as tribute organisers in 2012, continued this practice.

Tribute In Light

These brief interludes of darkness during the nightlong tribute provide a unique opportunity for the scientists to quantify changes in bird behaviour in several ways during the alternating periods of light and darkness.

“We had more than 20 wonderful volunteers on the ground counting birds to confirm what was happening in the beams,” says co-author Andrew Farnsworth at the Cornell Lab. “We also used remote sensing tools, including data from local National Weather Service radars, to understand the density and movements of the birds. Acoustic monitors recorded call notes and captured the vocal behavior of birds in the beams. And we ran computer simulations to try to better understand the dynamics of the patterns we were observing.”

When the tribute was illuminated, the study’s authors found that densities of birds over lower Manhattan could reach 60 to 150 times the number that would typically be found in the area at that time. The concentrating effects of the intense light on the birds reached as high as 4 kilometres (2.5 miles). The impact on birds was consistent even on clear nights. (Many previous artificial-light studies focused on nights with poor visibility.) When the light beams were turned off, the birds dispersed within minutes to continue their migrations.

Although Tribute in Light provided a way to measure a specific instance of light attraction, bright nighttime lighting poses problems for birds, even in rural areas. The study’s authors point out that one solution is relatively simple.

“We recommend building lights be turned off for as much of the night as possible, but at least from midnight to dawn during migration season,” says study co-author Susan Elbin of New York City Audubon. “This is true for areas around homes as well as other brightly lit areas such as sports stadiums, construction sites, offshore oil rigs, and large buildings. Migrating is already hard enough for birds without this added danger from artificial light at night.”

The full paper High-intensity urban light installation dramatically alters nocturnal bird migration can be accessed here

Alarm over decline in flying insects

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Comma. Photo by Mick DrydenFrom BBC News

It’s known as the windscreen phenomenon. When you stop your car after a drive, there seem to be far fewer squashed insects than there used to be. Scientists have long suspected that insects are in dramatic decline, but new evidence confirms this.

Research at more than 60 protected areas in Germany suggests flying insects have declined by more than 75% over almost 30 years. And the causes are unknown. “This confirms what everybody’s been having as a gut feeling – the windscreen phenomenon where you squash fewer bugs as the decades go by,” said Caspar Hallmann of Radboud University in The Netherlands.

“This is the first study that looked into the total biomass of flying insects and it confirms our worries.”

Bumble bee. Photo by Mick Dryden

The study is based on measurements of the biomass of all insects trapped at 63 nature protection areas in Germany over 27 years since 1989. The data includes thousands of different insects, such as bees, butterflies and moths. Scientists say the dramatic decline was seen regardless of habitat, land use and the weather, leaving them at a loss to explain what was behind it. They stressed the importance of adopting measures known to be beneficial for insects, including strips of flowers around farmland and minimising the effects of intensive agriculture.

And they said there was an urgent need to uncover the causes and extent of the decline in all airborne insects. “We don’t know exactly what the causes are,” said Hans de Kroon, also of Radboud University, who supervised the research. ”This study shows how important it is to have good monitoring programmes and we need more research right now to look into those causes – so, that has really high priority.”

The finding was even more worrying given that it was happening in nature reserves, which are meant to protect insects and other living species. ”In the modern agricultural landscape, for insects it’s a hostile environment, it’s a desert, if not worse,” said Dr de Kroon. ”And the decline there has been well documented. The big surprise is that it is also happening in adjacent nature reserves.”

Honey bee. Photo by Mick Dryden

The loss of insects has far-reaching consequences for entire ecosystems. Insects provide a food source for many birds, amphibians, bats and reptiles, while plants rely on insects for pollination.

The decline is more severe than found in previous studies. A survey of insects at four sites in the UK between 1973 and 2002 found losses at one of the four sites only.

Dr Lynn Dicks, from the University of East Anglia, UK, who is not connected with the study, said the paper provides new evidence for “an alarming decline” that many entomologists have suspected for some time. “If total flying insect biomass is genuinely declining at this rate (around 6% per year), it is extremely concerning,” she said. “Flying insects have really important ecological functions, for which their numbers matter a lot.”

Download the full report More than 75 percent decline over 27 years in total flying insect biomass in protected areas here