Not grousing about grouse

grouse
verb: to complain; to grumble

Yesterday I returned from a 17-day trip to Namibia and South Africa and after a string of special sightings, grousing is exactly what I wasn’t doing. One particular highlight was sightings of an order of birds I have never been lucky enough to encounter before.

Sandgrouse belong to the bird order Pterocliformes. This came about after they had previously been placed in two other orders. Firstly, they were included in the Galliformes, where the true grouse reside. They were placed here due to their anatomical similarities to the true grouse, although later on there was the realisation that this was not a result of genetic similarity but of convergent evolution (where two or more unrelated taxa evolve similar features, for example echolocation in the case of dolphins and bats). The next order they were included in was the Columbiformes which also contains pigeons and doves. This was because it was thought that they employed peristalsis in the oesophagus to suck up water – a pumping action which can draw liquid into the gullet – which is unusual in birds. Although now it is thought that this is incorrect, which stimulated the choice to place them in their own order.

There are sixteen species of sandgrouse species, found mostly in Asia and Africa. There are also some species in Europe such as Pin-tailed and Black-bellied which are found around the western Mediterranean. One has even made it to the UK: while most sandgrouse species are sedentary or make seasonal altitudinal movements at most, the Pallas’s Sandgrouse, which is usually found in central Asia, can be irruptive. Large irruptions have not been experienced in Europe for decades although they did occur regularly in the late 19th century. One irruption lead to thousands flooding into the UK and even breeding in a few locations.

As an order, they are well known for their drinking habits. Many species travel for miles to visit waterholes daily, where they can drink enough water in just few seconds to last them the 24 hours until the next visit. They are also famous for how they supply water to their young before they are able to fly to waterholes. The adult’s downy breast feathers are able to soak up lots of water, from which the chicks drink.

To avoid competition, different species visit waterholes at different times. This regularity makes waterholes ideal places to see many sandgrouse species with ease. During our stay at the Okaukuejo Camp in Etosha National Park, Namibia, we noticed that there was a poster by the reception which mentioned that Double-banded Sandgrouse visit the waterhole 40 minutes before sunrise and Namaqua Sandgrouse visit between 9am and 10am. We were lucky enough to have a chalet right next to the floodlit waterhole which is the main attraction at the camp. I was not going to refuse an opportunity to see my first sandgrouse species, so the next morning at 6.10 am I sat on a bench overlooking the waterhole. It wasn’t long before the first Double-banded arrived on the edge of the waterhole; at first it was only one or two at any time but before long there were at least thirty at once. Considering it was pitch-black everywhere around the floodlit waterhole, I was impressed.

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Due to the light my camera was set to a shutterspeed of 1/4, fortunately when they first landed the sandgrouse had a habit of staying stock still for a few seconds to check for danger before proceeding to drink.

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A female Double-banded Sandgrouse.

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Some sandgrouse smudges and a couple of less-blurry males.

After breakfast we headed out on a game drive on the semi-arid plains of the park. It was the dry season so waterholes were in low supply, so much so that individual ones are marked out on the map. At 9.45 am we arrived at the first waterhole of the day, on the edge of the Etosha Pan. This pan, when it wasn’t a pan, would have been the third largest lake in the world after the Caspian Sea and Lake Superior. It is not entirely known how the lake dried up however tectonic movements changing the course of the river that fed it seems to be the most plausible explanation. Nowadays, its dry, salt-encrusted state causes a few small water-bodies to draw in animals from a very wide radius.

Among the springbok, gemsbok and other mammals that this particular waterhole had attracted, I noticed a good number of what I originally thought were Cape Turtle Doves. Although after a closer inspection I realised that they definitely were not these but Namaqua Sandgrouse, at exactly the right time in the morning!

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The light was better for our sighting of the Namaqua Sandgrouse than for the Double-banded Sandgrouse, however the distance was compromised. This image shows a male on the left and a female on the right.

After having never previously laid eyes on these fascinating birds, seeing two species in just one day was certainly more than I expected. Although a few days later, it became evident that the trip was about to become even better for sandgrouse. We were at our final destination of the Namibia leg of our travels, a lodge named Ondekaremba near to the Windhoek Airport. We had dropped our bags off at the lodge before then returning the rental car at the airport (then subsequently hailing a taxi for our return to the lodge and a hotel transfer to the airport the following morning). We were beginning to think this was not a good idea as the access road to the lodge was a four-mile dirt track weaving through the bushveld and a dry riverbed which was unforeseen. However, it certainly became worthwhile when my mum spotted some movement on the side of the road. My dad, seated on the nearest side of the car to the birds, proclaimed that they were sandgrouse which lead to my panicked scramble across the backseats. By the time the car had come to a stop they were so close that I had to lean right out of the window to get a view of them below us. There were two, presumably a male and a female. The female was hard to see in the roadside grass although the male was walking slowly unobscured along the road itself. Compared to the poor light for the Double-bandeds and the distance involved with the Namaquas, I had no excuses with these birds. Luckily, in my opinion I don’t need any! What made this encounter even more memorable was the fact that they were a third species: Burchell’s! I couldn’t help feeling that my luck was well and truly in. Three out of the four species inhabiting Southern Africa in less than a week is not bad going.

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The male Burchell’s Sandgrouse.

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This species is known for travelling around 100 miles each day to its favourite waterhole.

 

 

 

 

 

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Species no. 3000!

Admittedly Stratiotes aloides, known vernacularly as Water-soldier, is not the most desired plant to have in an ecosystem. It is possible that it is native in East Anglia and Lincolnshire however in Sussex, where this species became number 3000 on my pan-species list, it is more likely to be introduced.

Yesterday I joined the Sussex Botanical Recording Society on a visit to Court Lodge Farm on the Pevensey Levels, which possesses a rich assemblage of aquatic plants in the many ditches. Some special species recorded included Potamogeton obtusifolius (Blunt-leaved Pondweed) and Petroselinum segetum (Corn Parsley), the latter growing on the banks of the ditches rather than within them as was the case with the pondweed.

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An example of one of the ditches where we were recording. The majority of the water plants you can see in the photo would  be Lemna trisulca (Ivy-leaved Duckweed), Elodea nuttallii (Nuttall’s Waterweed) and the aforementioned Potamogeton obtusifolius (Blunt-leaved Pondweed).

Although despite these Levels specialities being present, for the ditches it is hard to escape the colonisation of several non-native invasive plants. Fortunately we didn’t come across any ditches which were dominated by these unwanted waterweeds however both Azolla filiculoides (Water Fern) and Hydrocotyle ranunculoides (Floating Pennywort) were found along with the robust growth of Water-soldier.

Water-soldier can be quite problematic for native flora. Small populations can, if left undisturbed by boats or large numbers of waterfowl, develop into armies. These can completely annex stretches of canals or ditches, out-competing ‘friendlier’ water plants for resources. The following quote is from the Water-soldier’s species account in the recently published Flora of Sussex: “On Pevensey Levels it has spread considerably, and in 2010 was found to be completely covering a ditch for several hundred metres”.

Despite this, I find its biology quite interesting. In the autumn it will begin to stop photosynthesising, and gradually lose the gas in its leaves that keeps it afloat. It will sink to the bottom of the ditch or canal where the water is unlikely to freeze. In the spring the increased strength of the sun’s rays will penetrate deep enough to allow the sharp, serrated, sword-shaped leaves to photosynthesise again, producing oxygen which gives the rosettes their buoyancy.

I was not originally planning to write a blog post on the Water-soldier until I realised today while inputting yesterday’s finds into my list that it fits into the 3000th slot. I am quite relieved that I have managed to reach this milestone, as the target I set myself in a blog post I wrote when I reached 2000 was to record my 3000th species before my 15th birthday. As of today I’m 14 years, 11 months and 1 day old. So I reached my target, but only just. It is hard for me to imagine stopping pan-species listing, however with upcoming GCSEs and A Levels I imagine I might have to slow down a little. But to keep it ticking, I have decided to set myself another target: 4000 by the end of 2019. Wish me luck!

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Two plants surrounded by Frogbit (Hydrocharis morsus-ranae) resembling miniature water-lilies.

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The snow-white flower of Water-soldier. The flowers are not seen too often, with the main method of reproduction being vegetative: the lowest leaves of the plant have axillary buds which will detach when the leaves decay and can disperse long distances before resprouting. This species is what’s known as dioecious – this means that male and female flowers are found on different plants. For some reason, there are very few if any male plants in England, so all reproduction in this country is vegetative as described above.

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The four or five plants in the photo here represent about half of the largest population of them I saw, luckily it hasn’t reached the levels of dominance seen at other parts of the Levels.

Orchid on the Hill

The Early Spider-orchids Ophrys sphegodes at Castle Hill NNR have one of the best views of the South Downs as well as Brighton to their south-west. On the northern edge of Woodingdean, a chalk grassland slope supports this nationally scarce species, which has only a scattered distribution along the South Coast from Dorset to Kent.

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This orchid is named after its appearance, with its flowers apparently resembling the abdomen of orb-weaver spiders. However, its flower shape has evolved so that it resembles bees, which come to try and mate with the flower, known as pseudo-copulation. This is also the case in the perhaps more appropriately named Bee Orchid for example. To complement the shape of the flower, these orchids also release the scent of female bees which further entices the male bees to unknowingly pollinate the plants.

However this technique may show to be detrimental towards the success of the species in the face of climate change. Despite the strength and accuracy of the scents wafted by the flower, they cannot compete with actual female bees. Therefore, the plants most likely to pollinate and reproduce successfully are those which blossom after the male bee has emerged although before the females. Although sadly warmer spring temperatures are pushing the phenology (life cycles) of these two species out of sync.

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It is also interesting to observe the variation in the exquisite patterns shown on different individual flowers, such as these:

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Travelling to find these orchids (a new plant for me) was a perfect break from revision. Despite their rarity, there are several reliable sites such as Durlston Country Park and Dancing Ledge in Dorset, Samphire Hoe in Kent and of course where I visited today, Castle Hill NNR in East Sussex. I would definitely recommend looking for them before they stop flowering in early June!

 

Mid-March Moth Madness

After a snowy delay, last weekend it seemed like spring had finally sprung and temperatures rose into double figures. Looking at the forecast for this weekend and into next week however, it looks like the wintry weather will return once again which is very odd for this time of year. I’m usually a fan of a bit of snow, but only at the appropriate times of year. So I decided to write this blog post to try and keep my spring feeling going for as long as possible, before the snow showers begin to move in from the east again.

Saturday night was the first time I have put my moth trap out this year. In previous years I have been a little more keen, with very little reward and sometimes even null counts at this early stage in spring, so I decided to hold it off until now. And with the Beast from the East only about a week gone, my hopes were not particularly high. Although I was in for a surprise.

Most of the time, I just leave my trap out for the whole night and check it in the morning. However, on the off-chance of something notable (or anything at all!) being in there, I decided to look down from my bedroom window just an hour or so after switching on the light. To my surprise I saw what seemed to be an Oak Beauty already within the trap, so I rushed down to check if there was much else about.

To my immense surprise, there were at least 20 moths flying around the trap and on the nearby house wall. Most were March Moths as well as several more Oak Beauties, along with a couple of Tortricodes alternella and a Common Quaker. Already we had recorded around twice as many moths as I usually get in an early-spring night!

I was more than keen to check the trap the following morning. Unsurprisingly, there were moths everywhere, with the final tally being 55! I would be happy with that in May or September, let alone the first half of March! I will run through a few of the stand out highlights:

Small Brindled Beauty

This was the rarest moth that I caught last night, and the second time I’ve caught this species, the previous occasion being early March last year. It is most common in southern England, becoming rarer further north although classified as ‘local’ – found in less than 300 sites nationally. The females of this species are one of many winter and spring species that are apterous – lacking wings. The females of many of these apterous species seem completely unlike most moths to me, although I’m yet to find one myself.

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Small Brindled Beauty

Dotted Border

This species is unique among the early spring moths as it is one of the few Geometrid moths out at this time of year. In my experience it is usually the Noctuids (such as the Clouded Drabs, Hebrew Characters and the Quaker species) that are the most commonly trapped, although the most abundant species caught during this night were the 18 Oak Beauties which is a slightly unusual Geometrid species. The Geometrids can be distinguished by the way they hold their wings; most Geometrids hold their wings out to the side whereas most Noctuids fold their wings over their abdomen.

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Dotted Border

This species can usually be identified by the row of dots running along the bottom of the wing which you can see in the photo above. However, it is a variable species throughout its distribution and there are forms which are very dark making the row of dots (the dotted border) very hard to see.

Clouded Drab

This species is quite common especially where its foodplant Oak is plentiful although, despite its name, it is can be really nicely patterned. It is another species that is really variable, with many colour forms. We caught three, one of them in particularly was particularly good-looking, with its pattern enhanced by the flash on my camera.

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Clouded Drab

Hopefully the upcoming cold snap will be the last of the winter, and spring will be allowed to continue unabated. I look forward to moth trapping further once it warms up again, hopefully we’ll continue with some good numbers!

Final Tally

  • Common Quaker 3
  • March Moth 9
  • Oak Beauty 18
  • Hebrew Character 4
  • Tortricodes alternella 2
  • Small Brindled Beauty 1
  • Dotted Border 5
  • Clouded Drab 3
  • Small Quaker 8
  • Chestnut 1
  • Brindled Pug 1

 

The invasion continues

This winter Europe has been host to an avian phenomenon I wasn’t even aware was possible. Hawfinches in the UK are very rare and elusive birds, mainly confined to large areas of forest such as the Forest of Dean and the New Forest. Indeed, in February 2017 I hitched a lift with Josie Hewitt for a two hour journey to the New Forest especially to see these birds, and it’s funny to think how oblivious I was to the fact that it would become clear by the end of the year that it was an unnecessary trip.

I don’t think anyone is quite sure why, but this winter Hawfinches have truly irrupted from their core European breeding grounds. The areas where these usually strictly forest-dwelling birds have been recorded over the past few months is incredible, including the Moroccan Sahara, Kuwait and Alaska! In Sussex, where hardly any are seen outside of West Dean Woods, flocks have surpassed 100 individuals at locations scattered across the county. I am not aware of any previous such invasions of this species, so it definitely feels like a once-in-a-lifetime experience.

Last weekend, I was ringing at fellow trainees Dave and Penny Green’s garden near Wisborough Green. I had heard that there were one or two Hawfinches visiting their large Yew tree, so I was fairly hopeful that some brief sightings would enliven our ringing session a little more. However, it soon became clear that my expectations were far too low! We were treated to an almost constant presence of Hawfinches throughout the day, at least 6 I think and possibly up to 10 were visiting the Yew at one point. This allowed for some absolutely brilliant views of this normally tricky-to-see species.

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Beautiful male Hawfinch

As you can see from the photo, Hawfinches have a massive bill. These have evolved to crack really hard nuts and seeds, such as cherry stones which they can easily crack. They certainly are attractive, chunky finches and I do hope that the invasion continues, and perhaps there’ll be a bumper breeding season for them here in the UK!

Myrmecomorphy in action!

Sunday the 15th October was the date of the Amateur Entomologists’ Society field meeting at Rye Harbour Sussex Wildlife Trust reserve. It’s not often that I do a focused invertebrate hunt at this time of year, so I was looking forward to seeing what we found.

The field meeting was unexpectedly good on the arachnid side of things. I had no idea that the reserve was so rich in numbers and species of spider. We spent most of our time in a compartment of saltmarsh and shingle, where the shingle was really shallow. The layer of shingle was about two stones thick, and the soil beneath it was compact. This meant that the spiders could not escape deeper into the shingle as they would at most shingle sites.

One of the highlights of the field meeting spider-wise was the fantastic Myrmarachne formicaria. As the scientific name suggests, this species of spider is an ant-mimic (the prefix ‘myrm’ means ‘ant’ and a formicarium is an ant farm). The mimicry of ants in the animal kingdom is known as ‘myrmecomorphy’ and is quite common across a number of invertebrate orders. Invertebrates that are known to be ant mimics include young grasshoppers, true bugs (Hemiptera), flies, beetles and of course spiders.

But why do so many invertebrates mimic ants? Ants are known among the predators of invertebrates to be aggressive or distasteful, so they are avoided. And the predators will also avoid any insects that look like them, but lack any means of defence such as the young grasshoppers. This is known as Batesian mimicry, as it was first described by H W Bates. Some ant mimics have even gone as far as to mimic the ants chemically as well, by emitting ant-like pheromones, which is referred to as Wasmannian mimicry.

However, Myrmarachne formicaria may mimic ants for a different reason. It is thought that some spiders mimic ants not only for protection against predators but also so that they can hunt the ants themselves. Ants will overlook the spiders as one of their own colony, giving the spider the perfect opportunity for a meal. This type of mimicry is aggressive mimicry. As you can see from the photo below, the spider has a long abdomen, which helps it to resemble an ant.

Myrmarachne formicaria male by Evan Jones

Myrmarachne formicaria, photo by Evan Jones, one of the field meeting attendees.

Myrmarachne formicaria really was a fantastic sight, and I hadn’t personally seen anything like it before. It was fascinating to learn how and why so many different invertebrates mimic ants. The sheer number of ant mimics must indicate that ants are one of the most successful of all invertebrates.

Technology: Help or Hindrance?

My recent blog post – Youth & Nature: Is There Hope? – sparked a lot of interesting discussion on the role that technology plays in connecting and inspiring young naturalists. I mentioned in the blog post that screens tend to consume hours of young people’s time that could profitably be spent outdoors. However technology clearly has many benefits as well. In this blog post, I’ll mention some of the many ways in which technology is aiding the development of young naturalists.

July 2016, the incredibly popular game Pokemon GO was released. The objective of the game is to go in search of Pokemon characters, and ‘catch’ them. This got hundreds of millions of people outside, doing an activity which could be equated to geocaching. But the problem was, were they really interacting with the natural world, or were they too engrossed in their screens to pay attention?

In my opinion geocaching is much better for getting children outside. It’s like a treasure hunt, where families can follow co-ordinates through wild landscapes to find hidden boxes. Many nature reserves and other wild spaces have geocaches hidden inside, and the fact that you are actively looking for a box in real life rather than on a screen means that you are far more attuned to the natural world around you. And when you’re out there, exploring, looking for geocaches, the chances are that you will bump into some brilliant wildlife.

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Furthermore, technology has been incredibly important in connecting most of the young naturalists I know today. Using platforms such as Twitter and Facebook, young naturalists have been able to share their work and discuss ideas. Without a doubt, social media has given many young birders, botanists and all-round naturalists the support they need from others to get them going.

It may be, for some naturalists, that the daunting prospect of identifying things that they see is off-putting. One used to have to spend hundreds of pounds on literature to  master even a single group like fungi before technology. Now on social media like Twitter and Facebook there are accounts, groups and pages especially to help people identify what they have found. One example is the @MothIDUK Twitter page set up by Sean Foote, which answers many ID queries from puzzled naturalists every day. Without a doubt accounts, groups and websites like this are making naturalists’ lives far easier, and allowing them to enjoy nature that extra bit more.

Collins Bird Guide is one of several apps that have increased people’s connection with and knowledge of the natural world.

Finally, there’s no way that I would be writing this blog post without the help of technology. I wouldn’t be able to raise the issues of youth & nature, and the benefits of technology. I’d like to thank people like Calum Urquhart, Dara McAnulty, Megan Shersby, Josie Hewitt and others who reminded me that technology, although it can distract from the natural world, can also be incredibly useful for connecting existing naturalists and inspiring new ones. There are probably several points I’ve failed to mention here; and as technology advances I’m sure that the number of ways in which it benefits naturalists will increase.