Insert Lore - Live Butterfly Garden

Todd received a very cool gift for his birthday - a kit which permits observation of the caterpillar to butterfly lifecyle, in all its glory. The butterfly 'garden' as it is called is essential a cylindrical butterfly net. On opening the kit there is a certificate, which is used to order the live caterpillars, and you can trigger the process by post or via the internet. 

I followed the internet option and selected a time slot for delivery. The caterpillars arrived on May 2nd and were absolutely tiny. When you see them like this it is hard to believe some of the British species can swell into absolute monsters like the Elephant Hawk Moth caterpillar (see previous article where we found one of these true mini-beasts!). 

Unfortunately I took the first picture a few days after they arrived and by this time our five eager caterpillars had trebled in size. 

The species we received were Painted Lady caterpillars (Vanessa cardui) and, unsurprisingly, they turn into Painted Lady butterflies! You get five caterpillars in a sterile pot, which contains enough food (not typical leaves but a special formula) to facilitate rapid growth and subsequent chrysalis construction. You don't open the pot, it is just a case of observation. 

Four of our charges morphed into monsters and effectively constructed cocoons. The fifth didn't manage to build a suitable metamorphosis chamber, largely on account of the other four deciding he would provide an excellent nutritional resource! Yes, caterpillars will eat their own and, of course, the probability of this occurring is higher in a confined space. Thus we were left with four very interesting cocoons and one caterpillar without a head. 

Look at the size of them after only 9 days! 

After about ten to fourteen days the caterpillars crawled up to the container lid and suspended themselves in preparation for metamorphosis. It is remarkable how much silk they produce and it is not something people regularly associate with butterfly larvae, but they were spinning threads all over the place and ultimately reached the top of their micro-habitat by means of this series of biological nets. 

The cocoons/chrysalides have now been removed from the pot and sit inside the butterfly garden, as per instructions. I will post pictures of them shortly, along with the butterflies, which should be emerging any day now. 

Spotted Python Eggs

The Spotted Pythons were cooled down this year to simulate proper autumnal conditions. I wasn't certain copulation was taking place, but it transpired almost all of it occurred in the dark seclusion of the stone cave near the main heat source. 

I caught them tied a few times, as did Todd, and so it was just a case of whether the female had enough body weight and the male was fertile. This year was the first time she was large enough to breed (I had worked hard feeding her up during 2011 to ensure the greatest chance of success). 

It was fantastic for the boys to witness the reality of reproduction. There was no point talking about birds and bees or storks with the amount of questions these two have! Best to let nature explain and then support with additional words. 

Certainly the path from copulation to egg laying has not run according to the text books. They were introduced to each other around November and the temperature gradually reduced (via habitstat control) until it rested around 23 degrees. As the weeks progressed (with food having also been withdrawn) biochemical signals began to slip both animals into breeding mode. 

A female python's ovulation is different to the widely accepted human definition. Rather than releasing the eggs on a regular basis, which may or may not be met by the male's seed, the female snake will ovulate once successful mating has occurred and she is literally ready to push the eggs down to the waiting spermatazoa. At this point a noticeable swelling is observed - as if she had consumed a very large prey item. I didn't witness the event, but it is possible it occurred while she was in the cave or that it was less pronounced and therefore not obvious (which does happen). 

About two months ago we had the pre-lay shed and I kept the faith. It is approximately 30 days from this point until eggs appear. After this pre-lay shed the female normally shows no interest in mating, but I saw them tied at least once more after the event. That is unusual. 

Also the female did not appear at all broad or full, she always remained rather slim looking, and this added weight to our opinion that the pairing had failed.

Anyway 60 days after what we assumed was the pre-lay shed, and with all hope diminished, she did in fact lay a clutch! This caught us all by surprise and I was certain it wouldn't happen this year. I lifted the cave up, in order to confirm she was ok (as no hunting behaviour had been observed), and she was coiled in a perfect spiral. I had never seen her lay like this before and, on shifting her head slightly, I saw a perfect, full, white egg. The female is normally good at deciding which eggs are infertile and removing them from the clutch, so at this time it is looking positive. 

Female pythons are maternal and will remain coiled around their brood throughout incubation. They will also twitch their bodies to raise the temperature and maintain optimum conditions. This is peculiar to the family Pythonidae.

Fingers crossed we are in a position to reveal babies. The longer a female holds on to the eggs the less time they take to hatch, so based on what we have witnessed it could be anything from 38 - 58 days before miniature serpents venture forth into the big, wide world. 

The Blackbird's Nest

We we are at the Norwegian Church in London recently and, after the boys had completed their studies and eaten lunch, we ventured into the back garden for a bounce on the trampoline and kick of the football. 

Glancing across to the ivy, I suddenly caught sight of a bird nest constructed in an unusually low and exposed position. Indeed it was receiving some interest from the local avians, which can't have been ideal. 

The kids were keen to take a closer look at the nest and, seeing as it was so low, it wasn't difficult to hoist them into an ideal viewing position. We were very careful not to disturb the nest and I snapped the close-ups by holding the camera directly above and avoiding direct contact. 

Checking the books it would appear this was a Blackbird's nest (the blueish background and vague brown speckles being indicative), but a close call between that and a House Sparrow. The latter seems to have a more pronounced contrast between the brown and blue.  Hard to tell if the eggs had been abandoned, but there were some signs of pecking, which is commonplace during spring, as other species attempt to reduce the competition for food. Either way we left them in peace - carried in the capable hands of mother nature. If any are destined to hatch and thrive then it will happen, otherwise they may provide a useful food source for other creatures in the area. 

Nests are truly miraculous creations. They are right up there with spiders' webs in the complexity stakes and every species of bird builds a nest in a unique fashion. Remarkable that thousands of years have rendered these skills instinctive and thus provided a multitude of birds with the best chance of survival.

It would be wrong to suggest, however, that all bird nests are complicated structures. Many are nothing more than a dent in a sand pile or a scoop from a pile of rotting vegetation. Others are incredibly intricate - species such as the Weaver finch (Ploceidae) construct hanging nests with various chambers. Swallows (Hirundinidae) utilise mud to establish well protected nests, often located in precarious positions on the edge of cliffs, drain pipes or even high up on adjoining walls (see below). 

Evolution of nest building will have been dictated by a number of factors, including available substrate, intra-specific competition and predation levels. There are many examples of convergent evolution, which we would expect to see and, consequently, many species build superficially similar structures. 

Bird nests aside there are many examples of external construction in the animal kindgom - ranging from Caddis fly larvae and their armoured mobile homes to termite mounds and spider webs. Utilising the environment, huge numbers of creatures have honed techniques until reaching a point where their kind has the best possible chance of survival and reproduction. We walk down the street everyday and pay no attention to the wonders that have been designed above our heads, but take a closer look and the average bird nest is one of the most amazing things you are likely encounter.