Monday, 17 April 2017
A study by Brighton and Reading Universities has suggested that there currently are around 150k urban Red fox (Vulpes vulpes) in the UK and that their numbers are increasing whilst populations of their rural counterparts decline (https://www.theguardian.com/environment/2017/apr/16/urban-foxes-number-one-for-every-300-residents-study-suggests). The numbers in particular city areas seem quite variable with the density being highest in Bournemouth (circa 23/ square Km); also high in London (circa 18/ square Km) but somewhat lower in Newcastle (circa 10/ square Km). The estimates are, however, partially based on reports by the general public and could be influenced by local enthusiasms for reporting wildlife. It is suggested that foliage in gardens is a factor that encourages the spread of this territorial predator but personally I think that local provisions of food (as waste or as material left outside for dogs and cats, along with the availability of the odd rat or wild bird) are more likely to determine the densities of these animals. Foraging for food in towns is likely to be more cost-effective for the fox than trying to make a living in the countryside.
Sunday, 16 April 2017
Saturday, 15 April 2017
Thursday, 13 April 2017
There is a novel report that a species of ant from the Ivory coast that raids termite nests will 'rescue' injured attackers from their own colony in response to an emitted 'pheromone' (https://www.theguardian.com/science/2017/apr/12/injured-ants-get-rescued-after-sending-chemical-sos-researchers-find). The chemical signal presumably differs slightly from colony to colony and does not really trigger genuine altruism. The rescuers come after trapped or damaged attackers (they will respond to an ant that has had 2 of its legs cut off by the scientists!). It does appear that rescued individuals can be active again after recovery. Damaged individuals from other colonies are treated as 'meat'. It seems most likely that this is a mechanism for maintaining the colony's stock of attackers for as long as possible (the more attackers, the more termites to process?). In some ways it is like the mechanism in worker Honey bees of not over-loading with nectar and pollen before flying back to the hive that maximises their longevity (and utility to the colony).