- Aug 10, 2015
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While that that seems an obvious conclusion, it is not necessarily the case. Let’s use a simplified example to explain why… In the wild, beardies can live between 5 and 8 years. Clutch sizes vary from 10 to 20 eggs and they can have multiple clutches in one year. Therefore, it would not be unrealistic to expect a female to produce 5 clutches of an average of 15 eggs in her lifetime i.e. 75 eggs. Only two young out of 75 need to survive and reproduce in order to replace the parents. This will maintain a stable population. Or to put it another way, 73 young have to perish. Many will starve, others will be taken by predators, some will die of disease or parasites, others from trauma. So removing several offspring from this one reproducing pair will ultimately have no effect on the population size. It probably just means that less will starve as there will be more food to go around. In biological terms, this is known as a sustainable yield. If you were to remove 60 or 70 of the offspring from this one pair, then you might start to affect population numbers.I think if people are taking something from the wild of course it will contribute to the decline.
Bluetongues seem to have faired better than bearded dragons in surviving in the suburban environment, but even they are becoming scarcer now. Blueys don’t need trees and fallen timber to perch on and are happy with low vegetation in which to forage. Vegie patches always provided a good feed of leaves, flowers and fallen fruit. The ubiquitous European Garden Snail is a great protein meal for them, one that they quite obviously relish. From my observations the fallen fruit of wild blackberries was another favourite meal, providing food towards the end of summer and into autumn, when other sources were less common. Unfortunately, backyard vegie gardens went out of fashion and although there has ben a recent resurgence, they are mostly grown in raised beds these days. An active eradication campaign has also seen a marked reduction in wild blackberry patches in urban areas, being considered a noxious, thorny weed. What we called ‘tin’ sheds used to be common. They were actually made of corrugated iron and as the sheets rusted, they were replaced and the old sheets often stacked down the back or around the side, providing excellent shelter for blueys. These have now disappeared for the most part. The same with woodpiles in houses, which are now heated by gas or kerosene (so called ‘oil heaters’) or electric air con. Without shelter and a food source, no blueys.
Water Dragons are a really interesting case. I reckon they are very intelligent for a lizard, as their genus name would suggest. They quickly learn what poses a threat to them and what does not. Where they can, they will make use of house yards adjoining their habitat. For example, using a concrete or bitumen driveway for basking, yet moving off quickly if the garage door is opened or a car turns into the drive. They will remain on the opposite side of a fence if there is a dog that will chase them on the other side, or will enter a yard where the dog could care less about them. They do the same around people. They will also scavenge food scraps left behind by people. They seem content to occupy smaller territories where food from human sources is more plentiful than food in their natural habitats. If given access, they will colonize artificial waterways and water bodies. IMO, given the right conditions, these lizards are not just urban survivors but urban thrivers.
There is nothing crap about that photo. Crystal clear - great focus. Good job!Heres a very crap pic of a wild beardie down the road from me.