Butterfly numbers down by two thirds: High-intensity agriculture reduces number of butterfly species in adjacent areas

From ScienceDaily

Meadows adjacent to high-intensity agricultural areas are home to less than half the number of butterfly species than areas in nature preserves. The number of individuals is even down to one-third of that number. These are results of a research team led by Jan Christian Habel at the Technical University of Munich (TUM) and Thomas Schmitt at the Senckenberg Nature Research Society and published in Insect Conservation and Diversity.

Germany is home to roughly 33,500 species of insects — but their numbers are decreasing dramatically. Of the 189 species of butterflies currently known from Germany, 99 species are on the Red List, five have already become extinct, and 12 additional species are threatened with extinction.

Reduced biodiversity also on areas around intensively cultivated fields

The research team recorded the occurrence of butterfly species in 21 meadow sites east of Munich. Of these study sites, 17 are surrounded by agriculturally used areas, and four are in nature preserves with near-natural cultivation.

The team recorded a total of 24 butterfly species and 864 individuals in all study sites. Specialists among the butterflies were particularly dependent on near-natural habitats, while the more adaptable “generalists” were also found in other grassland sites.

“In the meadows that are surrounded by agriculturally used areas we encountered an average of 2.7 butterfly species per visit; in the four study sites within the protected areas ‘Dietersheimer Brenne‘ and ‘Garchinger Heide‘ near Munich we found an average of 6.6 species,” adds Prof. Werner Ulrich of the Copernicus University in Thorn, Poland.

Negative impact of the industrialised agriculture demands rethinking

“Our results show an obvious trend: in the vicinity of intensively cultivated fields that are regularly sprayed with pesticides, the diversity and numbers of butterflies are significantly lower than in meadows near less used or unused areas,” explains the study’s lead author, Prof. Jan Christian Habel.

“Our study emphasises the negative impact of the conventional, industrialised agriculture on the butterfly diversity and shows the urgent need for ecologically sustainable cultivation methods. Additional field studies may aid in identifying individual factors responsible for the insect die-back and in implementing appropriate countermeasures,” adds Schmitt in closing.

See the paper Agricultural intensification drives butterfly decline here

Chough report: February 2019

White died this month due to health complications. Photo by Liz Corry.

By Liz Corry

Where to begin? The start seems a good place, but this start begins with an end. Two in fact, maybe three. Following? You will.

Wild breeding population suffers a setback

We sadly have to report the death of two choughs and a highly likely third. At the start of February, White was flying around with tatty feathers looking rough. He soon started showing symptoms of a syngamus issue despite ‘clean’ faecal samples. At the same time we noticed that Mauve, his partner, was not being recorded at the feeds. It is easy to lose an individual in a large flock, but pairs stick together.

White began to deteriorate so he was caught up and checked by the Vet. It took two days to trap him because the entire flock are now wise to our methods. Once locked in the aviary it was clear he was in trouble.

His was surprisingly good weight for a sick bird, which in itself was a concern. He has always been a larger bird, you can spot him in the flock based on size alone, but you would expect a slight weight loss.

Worming proved futile and he died a few days later. Post mortem results showed that his airways had become blocked by plaques of pus that had dislodged in the trachea. Why he had the plaques in the first place is unknown.

Whilst all this was going on Mauve was still absent. By the end of February, we had to conclude that Mauve was no longer with us.

White preening his partner Mauve in 2015 – their first season together. Photo by Liz Corry.

Mauve was one of the original group released in 2013. She had an interesting start to her free-flying life in Jersey as recounted in several of the earlier reports. White was brought to Jersey at the end of 2013 and released in 2014. They paired up in 2015 and a year later they had chicks of their own out on the north coast.

Cold case: chough PP012

On the same day that White passed, I was informed of a dead chough found in a garden at Grosnez. As Mauve had been missing I naturally assumed it was her.

On Sunday 17th, members from the Birds On The Edge team ran a stall at the annual Seedy Sunday & Wild About Jersey event (see below). Within an hour of the doors opening to the public I was approached by a lady from Grosnez. Seeing Lynne, our volunteer dressed as a chough, reminded her – she had a dead chough in her freezer!

The next 24 hours in the story were filled with twists and turns. In a nutshell, the lady had found the dead bird on her property in September 2017! At the time she wasn’t aware of the chough project, but had carefully double-bagged the body with a descriptive note attached. Nowadays she regularly sees the choughs flying over her land and knows what they are. As we all know, time ticks on and we forget things. Until you bump into a lady dressed as a giant chough!

Clearly this bird was not Mauve. The chough in question was Carmine, a wild chick hatched in 2017 belonging to Q and Flieur. She was one of the juveniles with syngamus who we had trouble trapping in the aviary. Since she was never medicated she probably succumbed to the infestation whilst flying around Grosnez with her parents.

A juvenile red-billed chough. Photo by Liz Corry.

We are very grateful to the lady for preserving Carmine and reporting it as we now have closure on a case. We can add this info to our dataset which aids future management plans.

If you do find a dead or injured chough in Jersey please call 01534 860059 or contact any of the project partners. We can come to you and collect the bird. All of our birds have metal leg rings on with a unique number. This will tell us who they are even if they have lost their plastic rings.

Replacement rings

Replacing missing rings on the choughs is turning into a never-ending challenge. Not helped by the birds either not showing at the feed or not staying inside when we try to shut the hatches.

A plastic leg ring found in grassland near the aviary. Photo by Liz Corry.

When White was trapped inside, I had the opportunity to replace Green’s missing rings. I could not fit the black gull-ring used with Green and the original release cohort. These need to be heated in hot water to open them without the material snapping; also tricky to fit one-handed. Since I was working alone without a thermos I made an on-the-spot decision. I fitted a black and white striped ring we happened to have in the ringing box.

These rings are normally used in the UK to identify a Cornish chough. As we don’t expect many of these to turn up in Jersey over the next few months I’m sure it will do as a temporary measure.

To get around the struggle of trapping the birds I tried the route of shutting the hatches after the birds had gone to roost. Fingers crossed at least one of the birds who still roost in the aviary would be a bird we needed. There were ten birds still at the aviary as the sun set. Two, maybe three, used the external roost boxes. The others went inside. The plan almost failed when the hatches didn’t close. I climbed the framework, silently cursing so as not to spook the birds, and manually closed the broken hatches.

Returning in the morning I was met with an interesting find. Earl and Xaviour had slept at the aviary. We thought they were back at Plémont having regularly been seen there before sunset. It now appears they are there for supper before flying back to Sorel to sleep. This finally meant Xaviour could have her two orange rings returned. Annoyingly she was the only bird in that group needing rings. We still have two Orange-right-only birds flying around. We need to see who if any they are partnered with to know who they are.

Potential new breeding pairs for 2019

Despite the sad loss of a breeding pair there is good news for the 2019 season. We have at least four new pairings thanks to the birds maturing. Zennor’s love for Skywalker is still going strong from the first moment she set eyes on him at Sorel last summer to a very exciting moment I can’t reveal until the March report!

Vicq, a foster-reared female has caught the eye of wild-hatched Osbourne. He isn’t even a year old yet, but it appears Vicq has staked her claim. And of course there is her clutch-mate Xaviour whose second year at Plémont may prove fruitful.

At present we have fourteen potential breeding pairs for 2019. I’m not sure how possible it will be for me to monitor them all throughout the season. I’m really hoping not to repeat the fiasco of last year when we miss-timed the hatch dates and were too late to ring the chicks. I may well be looking for volunteers.

Population census

The 2019 attendance record at the supplemental feeds has been relatively poor; around 60%. There are a few consistent absentees such as Earl and Xaviour who are spending more time back at Plémont. Other absentees have not been as easy to determine. The death of White obviously made us uneasy. What if we have lost more?

The dolmen at Grantez is one area choughs have been spotted this month. Photo by Liz Corry.

When possible, I have travelled around to known foraging sites to try and count the choughs. Of course to count them, I need to see them and I appear to be having issues with that. First off, Jersey’s potato fields are currently covered in plastic sheeting. In a way searching is easier because there are swathes of land where the choughs won’t be going. However, it also makes it hard to see anything when the morning sun reflects off the plastic.

Potato fields at L’Étacq covered to protect and encourage new growth. Photo by Liz Corry.

More fields near Grantez giving the illusion of water bodies when viewed from afar. Photo by Liz Corry.

I had a report sent in from one of the States’ rangers of two choughs in a field at Grantez one morning. Grantez is a perfect stop off for choughs with grazing sheep, a high vantage point to look over St Ouen’s Bay, two large fields grazed by donkeys, and a dolmen. Choughs love a bit of neolithic architecture. Of course, when I go up they aren’t there.

The same can be said for Le Pulec, Les Landes, and Plémont. All places I have had confirmed sightings this month. Fortunately we have a report of 13 at Les Landes at the same time we had 28 at Sorel. So at least we know we still have at least 41 choughs.

Not a chough – but perfect chough foraging habitat. Photo by Liz Corry.

Wild About Jersey

This year’s Wild About Jersey teamed up with Seedy Sunday a free seed exchange event. Le Rocquier School hosted the weekend with the Saturday (16th) dedicated to volunteer survey training for butterflies, bats, reptiles and the new Pond Watch scheme (takes over from Toad Watch). Sunday (17th) was the Seedy Sunday open day with various stalls, talks, interactive exhibits, and a guest speaker Alan Gardner, The Autistic Gardener.

Birds On The Edge had a stall staffed by Cris Sellares, Tim Liddiard, and myself. Conservation crops, a chough nest, and a dung beetle (soft toy) were laid out so the public could learn more about our work. I gave a talk entitled ‘Witches and Unicorns: how saving one species helps another‘. Trust me there is a link!

Drumming up support for Birds On The Edge. Photo by Liz Corry.

Not only did the event raise the profile of Birds On The Edge and bring to light the fate of Carmine, it managed to raise £1248.62 for Jersey Trees for Life. The money will be used to maintain and create more red squirrel bridges, across our Jersey’s roads.

Small mammal, big pain

Mice attempted to break into the chough feed-twice! Photo by Liz Corry.

The much ‘loved’ rodents struck again at the aviary. Droppings covered almost every surface in the keeper porch. Anything with the slight whiff of food about it had been nibbled including the first aid box! And then of course there was the ‘heavy duty’ storage box for the chough food.

Mice are smart. As evidenced by the fact the only place they chewed the box was the hinge – the weakest point. They didn’t succeed in reaching the pellet, but they did contaminate it with plastic shavings which meant it couldn’t be fed to the birds. As a temporary measure, I taped the hinge whilst I went to the local hardware store. It bought some time at least.

Plasterers metalwork is being use to add extra rodent-proofing to the aviary doors. Photo by Liz Corry.

With my zoo keeper thinking hat on I wandered around the store looking for an easy, cheap, will-fit-inside-my-Hyundai, solution.

Plasterers beading! At just over £2 a strip it made for a cheap and easy to fit edging strip to the door frame to stop mice and shrews from getting in. The metal work is flexible enough for a human to bend it by hand but sturdy enough to deter a mouse.

I also salvaged some builders metal work from the skip. Durrell’s HQ is currently undergoing repairs and the builders had just that week ditched some scraps. All I need now is for them to ditch their cutting tools as my Leatherman doesn’t fair well with the more robust stuff.

A metal bin has been donated to the project to stop the mice eating our supplies. Photo by Liz Corry.

 

Thanks to a charitable donation we were given a metal storage box for the chough food. The mice and shrews can only get into this if they work together to form ladder and flip the lid.

I wouldn’t put it past them. Just take a look at the camera trap image below from inside the aviary.

Spot the Mission Impossible mouse trying to reach the chough food. Photo taken using Moultrie camera trap.

Magpie-proof feeders mark II

A new design of chough-feeder. Photo by Liz Corry.

We now have another design of chough feeder in use at the aviary. The choughs successfully probe for food reaching every nook and cranny. Magpies are limited by their bill shape and length.

It doesn’t stay that clean for long and has room for improvement in terms of ease of cleaning. We also have to remember to screw the lid back properly.

I was lazy one evening, and screwed it back by hand. The next day I returned to find the choughs had freed the bracket and opened the lid!

Clearly their idea of slow-release feeding is not the same as mine.