Enter the Dragon

Its been a long winter, but finally we are starting to have some creative fun. A dreary eyed common lizard emerges from hibernation. 

It's been a long, almost everlasting winter, but finally it appears that spring is starting to gain back some dignity. As much as I like the large numbers of wintering birds and more observable mammals winter can drag on a little too much, especially when you are doing a challenge like this and you just want to get on with it. To have a realistic chance of rattling up the magical 3,000 species mark we need plenty of sun, plants and insects. Sun = fun, to me at least, as sun often means reptiles, especially on these cool spring days and there are few species groups (if any) that I like more than reptiles. We are fortunate to have four native species within the recording area boundary the Slow worm, adder, grass snake and common lizard. Hopefully we will get plenty of opportunity to take a look at each of these species in detail. Today let's take a closer look the common lizard.

Male common lizards have bright undersides, which are vibrant orange during the breeding season, this is just starting to show here. 

Although I first recorded the species back in early March, the species has become notably more active and abundant over the past week with the slight rise in temperature and reduced cloud cover. The common or viviparous (owing to it having live young in Britain) lizard generally starts to rouse from hibernation around February, with March perhaps a more usual time in Yorkshire. However common lizards are one of the most cold-tolerant (and widespread) reptiles in the entire world, with populations extending into the arctic circle. Basking is typically in sunny, south facing, locations, close to cover. I find these early emergers often bask in the mouth of the hibernaculum (area used to hibernate) or remain close to cover, to reduce the risk of sudden changes in temperature catching them off guard. As the year draws on they become far more nomadic. The same can be said about how they approach a given day with longer basking in the morning, with regular short feeding trips, these trips become longer and over a longer distance as the day goes on until eventually basking may cease for a period in favour of pure hunting.

Common lizards have well developed hearing and good sight, so if you want to get this close you need to be quiet and move slowly. 

Emergence in the spring occurs when the lizard has attained a core body temperature of around 15^oC in the hibernaculum, this is doubled when basking, to allow an operating temperature of approximately 30^oC. In spring males need to bask to complete spermatogenesis (sperm production), so a lot of time is dedicated to this, as it is in our other male reptiles at this time. The low surface to air ratio of the body often means they emerge before the adders, with which they often share their habitat. Interestingly females need to undertake a period of hibernation below 8-10^oC in Britain, lasting at least two weeks to allow ovarian growth, without this breeding is largely unsuccessful (warm winters are quite damaging for our wildlife in general). Basking is short lived in the summer, but in the spring and autumn we get a good opportunity to get a close look at this rather shy and retiring creature. If you do disturb a common lizard, just sit quiet and wait as they will often move to the same basking location some minutes later.

Lizards are well developed predators, with a large mouth, despite their small size.

Common lizards feed on a wide variety of invertebrates, I managed to observe one feeding on one of the numerous small spiders which are also waking from hibernation, earlier. Typical food includes insects (adults and larvae), centipedes, harvestmen and spiders, small worms, snails and grasshoppers. These prey items are largely detected by sight and sound (be quiet around lizards unlike snakes, who don't have ears). These lizards will often rapidly shake prey to kill it, before swallowing it whole. The mouth is filled with tiny back facing teeth. Although lizards do not bite people, they are very fragile so don't attempt to capture them unless absolutely necessary.

Not everybody likes spiders (I love them), but have some sympathy as just about everything feeds on them. Sub-adult Araneus diadematus.

Common lizards tend to occupy cracks, gaps, small mammal burrows, logs and rocks when they are not active. This one (pictured) was found in the root-ball of a fallen tree. Common lizards do not burrow and are poorly adapted for such activity, in comparison to some of the other lizards. They require features like these to escape their many predators which include corvids (crows), kestrels, common buzzards, hedgehogs, adders (more so smooth snake in southern Britain) and occasionally rats, weasels and even shrews. Unfortunately red-backed shrikes are extremely rare as a breeding bird in Britain but they will also frequently predate common lizards (there's plenty to go around up here guys). Life expectancy varies between lizard populations but 4-5 years is often about right, with 12 years being exceptional.

The base of the tail (just above the blurred root) shows what is known as the penal bulge, this is a good way of sexing males, if your struggling with the other features (not mentioned in the blog post). 

Common lizards are typically found around heathland, moorland and open woodland with less intensively farmed parts of North Yorkshire having about the best populations in the recording area. Common lizards are a local species (the common part of the name is in reference to commons, not the species status), with roadside verges, uncultivated field edges, coastal sand dunes, brownfield sites and cliff edges also used. Common lizards like habitat with a diversity of structure, i.e. different vegetation heights, logs, embankments, depressions. We also see a clear preference for water and humidity, with damp upland grasslands being particularly productive locally. These are insect rich and when close to raised dray habitat suitable for hibernation and loafing can be really productive.     

          

With no undue disturbance this chap was left to get on with his sunbathing. 

It was also good to find a tawny owl pellet close to the lizard, this can be compared with the pellets (barn owl, short eared owl and common buzzard) in the silent spirit post. The pellet was made up exclusively of bank vole a common component of the diet, as seen by the rusty red/grey fur in the pellet.