Archives for posts with tag: Biology

It was fantastic to read the review of citizen science that was commissioned by the UK Environmental Observation Framework (UK-EOF).

You can see details of the review here:

http://www.ceh.ac.uk/news/news_archive/Citizen-Science-Review-Guide_2012_59.html

As with any method there are positive and negative points associated with citizen science, but thankfully it is become more widely recognised as reliable method of data collection.

Personally, I feel the major benefit to this work is the connection to both science and the natural world that it cam instil. Many people go about their lives without giving a second thought to the fascinating world of urban ecology that is right in front of them.

Image

Pigeons allow anyone to witness amazing behaviour close up

Pigeons are often one of the first wild creatures children come in to contact with.

I also firmly believe that children can benefit immensely from being introduced to the natural world and that such early lessons can instil a life long love of the natural world. Citizen science can add an element of fun and even friendly competition to aid engagement.

Who hasn’t witnessed a child chasing a pigeon in a town centre?  I believe children taught from an early age to respect pigeons, rather than chase them may develop respect for the creatures we share our planet with.

Recently I heard a quote that I believe summarises the situation perfectly,

“Teaching a child not to step on a caterpillar is as valuable to the child as it is to the caterpillar.”

If we are to raise a generation of children willing to protect the rare and the unusual, we need to start at home with the familiar, and in my view, equally wonderful.

Pigeons appear to have an uncanny ability to defy all attempts at eradication by people who mistakenly believe they are a risk to human health.  In order for a population to remain stable, each pair need only produce two surviving offspring to eventually replace themselves. However, no individual can know the probability of any of its offspring surviving and therefore, must attempt to produce as many offspring as it can. Feral pigeons show iteroparity, that is, multiple breeding attempts over a life time and are known to pair for life. As R selected organisms, feral pigeons can respond quickly to favourable circumstances, producing offspring in a short space of time, which in turn can breed within 6 months.  In fact, the strong pair bond of adult birds allows clutches to overlap, with the female sitting on a new clutch of eggs whilst the male tends to the newly fledged youngsters.  Clearly, this highlights the very reason lethal control methods are ineffective.

Young feral pigeon

Feral pigeon youngsters look very similar to the adults – the beak and eyes often give the game away. Youngsters also squeak to the adults, hence young feral pigeons are often referred to as squeakers.

Schein’s 1954 study of feral pigeon recruitment found interesting results. Two sites were studied, a church steeple with multiple nesting platforms and a hospital. Nests were monitored from point of lay to fledging and the number of fledged young was recorded. The majority of the nests on the hospital study site were located within a central heating tower where temperatures remained warm and stable, whereas the ambient temperature of the church site fluctuated,  however, results showed very little difference between the survival probability of both flocks.

Of 152 eggs laid at the church site, 85 hatched, and of these, 47 fledged , giving a fledging probability of 0.309.

Similarly, of 293 eggs laid at the hospital site, 149 hatched and of these, 83 fledged giving a fledging probability of 0.283.

Given that temperature was shown to have little effect on the fledging probability of individuals of either flock and that both flocks showed similar figures, it can be suggested that other causal factors are involved.

Which brings me to the strange title of this blog…

Given the r selected nature of feral pigeons, food is a factor in the rate of offspring production, so I wonder how the changing face of the human diet affects this rate.

The fact that we are eating greater amounts of fast food is not in question, obesity levels have rocketed since this study was conducted. In 1950, 9.7% of Americans were obese, compared to 30.5% today.  Has the food available to feral pigeons today subsequently increased in both quantity and calorific content? If this is the case, what effect has this had on the probability of offspring fledging today in comparison to those in 1950?

A repeat of this study today may yield interesting results as it may be found that our increasing demand for higher calorie, convenience foods is causing a subsequent increase in one of the most adaptable species on the planet.

REF

Schein.W (1954) Survival records of young feral pigeons, The Auk,  Vol. 71, No. 3 (Jul., 1954), pp. 318-320