Spadefoot toads: an introduction

As those of you who follow my blog will know, I have a trip to Greece planned for October where one of the main targets is the Eastern spadefoot toad (Pelobates syriacus). Therefore I thought it would be a good idea to give some information on what a spadefoot toad actually is, as well as its adaptations and general habits as they are no ordinary toad!

Firstly, spadefoots are one of the most primitive Anurans (or tailless amphibians i.e. frogs and toads) with species found almost worldwide in Europe, North Africa, Asia and North America. But it is the European and American species which are the best known, and in my opinion the most beautiful. The English name ‘spadefoot’ is a reference to the sharp spade or tubercle found on the hind feet which are used for digging into the ground. In Europe three different species occur, the Common spadefoot (Pelobates fuscus), Western spadefoot (Pelobates cultripes) and the Eastern spadefoot (Pelobates syriacus). Whereas the first species is found even in parts of cooler places such as Denmark and Estonia, the other two generally prefer the more arid areas of the Mediterranean. All spadefoot toads are strictly nocturnal although occasionally during the breeding season in early spring they can be seen on the surface during daylight hours, especially if the humidity is high. The main external characteristics that separates them from other toads are the vertical, cat like eye pupils and their skin which is more moist than most toads. Furthermore the tadpoles of these toads are really huge, and in some parts of its range are the favorite meal of many bird species living near fresh water.

Western spadefoot toad (Pelobates cultripes from S-W France (C) Daniel Phillips

Western spadefoot toad (Pelobates cultripes) from S-W France (C) Daniel Phillips

The smaller Common spadefoot toad (Pelobates fuscus) from N-E France (C) Daniel Phillips

The smaller Common spadefoot toad (Pelobates fuscus) from N-E France (C) Daniel Phillips

The toads 'spade' used for digging itself back home below ground (C) Daniel Phillips

The toads 'spade' used for digging itself back home below ground (C) Daniel Phillips

Most spadefoots are a lowland species that occupy dry areas such as sand dunes, and cultivated land, but those from North Africa and North America can be found in deserts, such as Couch’s spadefoot toad (Scaphiopus couchii) from Arizona. It is this feature that fascinates me the most about these little toads, their adaptability to hostile environments where amphibians should not, in theory, be able to survive. I have been interested in spadefoots since I lived in S-E Spain, in a very barren region. Here the Western spadefoot toad (Pelobates cultripes) is scarce, and despite my efforts I could not find any adults, although frustratingly I could hear a male calling from beneath the surface of the water on one occasion but I could not locate it. My failure was due to the lack of rain, it only rains for about 2 weeks per year in this region and this is probably how long, on some occasions these toads are actually active. They awaken when the rains arrive and breed often in shallow rain ponds in areas such as farmland, the tadpoles develop very quickly so that before the ponds dry out they can reach metamorphosis. When the sun does reappear they use their ‘spades’ to dig back under the ground where they will remain until the next rains arrive. On some occasions these toads will have a year or two with no activity at all, if there is a sufficient lack of rainfall.

On the Greek island Lesvos, the Eastern spadefoot can be found as well as at some other locations on the Greek mainland. My German colleague Benny Trapp even thinks the toads present on Lesvos are considerably different to those on the mainland and could be a distinct subspecies of their own. Therefore it will be interesting to study them up close and see if it is possible to underline any obvious external differences in morphology. Unless some rain does arrive I may have to wait until the spring of 2010 before I can actually find some adults to examine.

Here is a short film produced by the Arizona Game and Fish Department of Couch’s spadefoot toad (Scaphiopus couchii) calling from its desert habitat

You can find additional photography of the European spadefoot toads on the links below:

http://www.euroherp.com/species/Pelobates_cultripes/

http://www.euroherp.com/species/Pelobates_fuscus/

http://www.euroherp.com/species/Pelobates_syriacus/

http://www.herpetofauna.gr/index.php?module=cats&page=read&id=45&sid=24

For those of you who know a little Spanish, here is a short post by my colleague from Spain about two tadpoles of the Western spadefoot toad (Pelobates cultripes) that we collected to raise and release back at the site. This tiny pond was the only area where we could find any sign of the presence of spadefoots in the arid region, but unfortunately not many tadpoles were present at the time. Here is the link to the Murcia reptile and amphibian blog:

http://herpetosmurcia.blogspot.com/2008/06/crecimiento-renacuajos-sapo-de-espuelas.html

By Matt Wilson

Corfu tortoise smuggling

Ever since I first visited Corfu when I was 16 years old I have come across the type of reptile enthusiast or Herpetologist or whatever you want to call them who collect animals from the wild for no other purpose but to sell them. The first time I visited my favorite tortoise spot I found myself confronting a 30 year old man who had two tortoises in a cardboard box that he intended to take home with him. At the time, even at the age of 16 I felt an obligation to spell out to this individual the damage he is causing to one of the most beautiful areas of Corfu by taking the tortoises away from their natural homes. Needless to say on this occasion the man handed the animals back to me so I could release them. Seven years later I still  meet such people, but thankfully not too often.  Only this April in Crete was I informed of a man who had been collecting Leopard snakes (Zamenis situla) which has been a regular victim to the pet trade over the decades, perhaps a reason why on islands such as Corfu it is so scarce now.

In the news recently the following article turned up: http://news.bbc.co.uk/1/hi/england/essex/8156846.stm I am very worried that by sharing my passion for these animals on websites such as my blog I am endangering such reptile further from these “reptile enthusiasts”. Corfu is really like a second home to me, I can even recognise individual tortoises year after year, and the knowledge that people are taking them for the pet trade is truely heart breaking. I am well aware that Corfu has been overcollected throughout the century, not just tortoises but snake species as well, and this maybe the reason why some of the most attractive species are so hard to find now.

It is a tough one, wanting to share experiences with people but at the same time not wanting to because of the risk of the wrong type of person reading them.

However, as I see each time I return to Corfu, many tortoises are thriving in some untouched areas, areas that only I and some trusted colleagues know about, so at least some will never end up in someones luggage.

Matt

One of my favorite reptiles: Hermann's tortoise (Testudo hermanni)

One of my favorite reptiles: Hermann's tortoise (Testudo hermanni)

By Matt Wilson

Lesvos!

Finally after years of planning and even a cancellation, I will be visiting the Greek island of Lesvos (Lesbos) this October. I have wanted to visit this island for so many years now, as it is relatively untouched by tourism and is also one of the largest Greek islands. Furthermore there are some great reptiles and amphibians to be found, such as Eastern Spadefoot toads (Pelobates syriacus), Dwarf snakes (Eirenis modestus), Sand Boa (Eryx jaculus) and an old friend of mine, the Ottoman viper (Montivipera xanthina), as well as a further 12 species of snake. I shall be staying in one of the most ideal areas for herps, an area consisting of sand dunes, temporary ponds, large river systems and cultivated land such as old olive groves. Although October is not the best time for such a trip, it can be very profitable if the usual September rains arrive, bringing all the animals back to life for a couple of months after a long, dry summer. Spadefoot toads are especially tricky, unless it actually rains whilst I am there I do not think I will find them, as most of their life is spent deep below ground in sandy burrows. Also unlike most amphibians they do not emerge consistantly, and usually only leave such burrows after heavy rain or when humidity is very high. In many dry areas, spadefoot toads can be active for no more than a couple of weeks per year, in which they must find all the food reserves possible, as well as time to breed. They have some of the fastest developping tadpoles of all amphibians that grow to a huge size, as often the tadpoles only have a couple of weeks to develop into toadlets before the ponds dry out.

I was hoping some friends and colleagues would be able to join me on this trip, as this year I have been fortunate enough to do my Greek field trips in the company of others. It has been a while now since I did a trip on my own, but maybe this is not such a bad thing, as often when I am searching alone I am like a man possessed, searching day and some of the night until I find what I want. Needless to say finding a nice species is alot more satisfying when you have spent days (sometimes weeks!) in the field on your own, rather than a colleague finding one and bringing it to you…Having said this field trips in groups are extremely rewarding, being able to see many more animals and sharing an interest with people very similar to yourself, hopefully in 2010 I will be able to do more trips like this.

In fact only one of my trips this year has been solely to find herps (Crete), and I can see this being the case on Lesvos, as there is simply too much to be explored and too many species to see for me to get distracted with anything else!

Matt

By Matt Wilson

Agamas on the up!

Around 1915 the Starred Agama (Laudakia stellio) was introduced to Corfu Town, the origin of these large lizards is unknown but it was speculated they arrived via trading ships from the Cyclades islands where this species is common. Needless to say they have established themselves very well in the town, along the walls of the two Venetian fortresses as well as the rural gardens and parks. In recent decades the lizard was even sighted quite some distance from Corfu town, such as tourist resorts several miles further south, and I myself could find a number of Agamas far inland in October 2004. I do not believe these lizards pose a real threat to the native reptiles and are in fact a nice addition to the wildlife of Corfu. Last week, whilst stopping at a cafe in Corfu Town I saw plenty of Agamas all around the cafe area, on the trees, walls and even under the tables! Last time I was searching for this lizard in Corfu Town five years ago I only found the odd animal, but they are clearly establishing themselves in great numbers now around the town, not such a bad thing in my opinion! Here are a few photos of some of the not so shy lizards that are now getting quite used to tourists watching and photographing them.

Starred Agama (Laudakia stellio)

Starred Agama (Laudakia stellio)

Starred Agama (Laudakia stellio)

Starred Agama (Laudakia stellio)

Old Venetian Fortress in Corfu Town, now alive with Agamas

Old Venetian Fortress in Corfu Town, now alive with Agamas

By Matt Wilson

Tree-frogs and Agile frogs

As Andrew Gray is an amphibian specialist we dedicated some time on Corfu to search for frogs. The island is not rich in amphibians but our efforts did produce a total of five different species. The main target was the European Tree frog (Hyla arborea) which thanks to some rain in late June we were able to find at one urban site. We could hear several males calling with the typical krak-krak-krak as we were walking through our resort in the evening. These frogs appeared to be making the most of a rain pool at the base of a construction site, not exactly a nice habitat but these animals have to make the most of any opportunity to breed. In total we found five males here, all sat calling at the water’s edge. For the second year in succession I have found tree frogs breeding in mid summer, perhaps and indication of how the environment is changing, as this species usually breeds in March and early April in Corfu. In addition we found another interesting amphibian, the Agile frog (Rana dalmatina) which has one of the longest leaps I have ever seen. Its a good job Andrew knows how to catch all types of frogs as I really struggle to get my hands on this species! Without doubt the easiest amphibians to find are the big Marsh frogs (Rana ridibunda) along with Epirus Water Frogs (Rana epeirotica) which we found in large numbers at several water sources, and we were able to catch a couple with the help of a net. The poorly recorded Smooth Newt (Triturus vulgaris) was found inside a concrete well on the Pandokrator mountain at about 900m above sea level, the first time I have seen them in this part of the island. Sadly though we were unable to find any Mediterranean Common Toads (Bufo bufo spinosus) or Green Toads (Bufo viridis), for some reason these two can be quite tricky to find on this island, but anyway we were quite happy with the frogs we had found!

The Common Tree frog (Hyla arborea)

The Common Tree frog (Hyla arborea)

Rana dalmatina

Agile frog (Rana dalmatina) which breeds in sand dune slacks on Corfu

Marsh frog (Rana ridibunda) the most common amphibian on Corfu

Marsh frog (Rana ridibunda) the most common amphibian on Corfu

By Matt Wilson

Summer trip to Corfu with two rare snake finds!

Well perhaps not rare, more like poorly recorded or locally common I would say…As expected it was very hot, but for a couple of hours in the evening we did some searches and had a few interesting results. Firstly, we found a Worm snake (Typhlops vermicularis) under a perfect, flat stone in a shady olive grove, as far as I know the first time the burrowing snake has been found in the summer. It usually retreats deeper under ground when the summer approaches as the ground at the surface is no longer as moist as it was in the winter and the spring. Another nice find was the Dice snake (Natrix tessellata), which was seen hunting in a great river habitat, only the second time I have seen this snake on Corfu where it is only found locally at some small sites in central Corfu. The Grass snake (Natrix natrix persa) is the far more common water snake relative which can be found all over the island. More photos will be posted later, everytime I visit Corfu new surprises always turn up, one reason why after eight visits to the island I will still be back for more!

Typhlops vermicularis

Worm snake (Typhlops vermicularis) found on 4th July

Typhlops habitat

Andrew Gray searching habitat of Worm snake

Natrix tessellata 2

Dice snake (Natrix tessellata) on the hunt, only the second record of this snake in almost 25 years!

Natrix natrix persa

The more common water snake on the island: Grass snake (Natrix natrix persa)

ropa river

Great river habitat, one of few water sources on Corfu that are home to both water snake species, as well as many other reptiles and amphibians

By Matt Wilson

Back in Corfu

Tomorrow I’m off to Corfu for a week, this time in the company of Andrew Gray, curator of Herpetology at Manchester Museum. Although it will be very hot and humid Corfu is so lush that even in mid summer it is possible for some nice observations. No specific species targets as I have found almost all of them on previous trips to the island. A new locality for Sand Boa (Eryx jaculus) will be checked, but we are unlikely to be successful with this secretive snake in the summer. Andrew, being an amphibian specialist is eager to see some frogs and toads, maybe the extremely humid conditions will help us in this respect, as it did for me in the same conditions a few weeks previously in Zakynthos. Back in a week so a report and photos will be posted.

By Matt Wilson