Monday, 9 February 2015

Garden Bird Comparisons - Rural & Sub-urban!

If you've been following my blog recently you will know that I took part in the Big Garden Bird Watch  on the weekend of the 24th of January, which is run by the RSPB. I collected all my data and made some graphs to compare the different species which visited over the hour duration. 

I wanted to take it one step further, so I collaborated with one of my friends who lives in a sub-urban environment. I got them to record their garden visitors over the same duration, at the same time in the day to ensure the fairest test possible. They also used the same types of bird feed as me, so as not to be biased towards a certain species. I then collected all the data from both locations (rural and sub-urban) and compared them using tables and graphs. What I found was very interesting…

As you would expect (or maybe you wouldn't) the rural setting (my garden) received a higher number of visitors over the hour, reaching 88 overall, with the sub-urban setting getting 50 visitors over the duration. This was what I expected, as rural environments generally have a higher population density of wildlife. The pie chart below clearly shows the difference between the number of visitors, comparing the two locations.

I did not want to stop there. I used excel to create a radial graph to display all of the collected data, revealing a very interesting thing. As you can see, the suburbs (represented by the red line) is very restricted within the 0-10 section, with most species barely making it out of the 5 zone. This is dramatically juxtaposed with the rural results (represented by the blue line), where there is a very clear spike with the Wood pigeon numbers and the Sparrow numbers. After a while considering why this was...

In a sub-urban setting, everything is relatively similar. The gardens are near identical, and their are rarely any major features (such as a river, reed bed or woodland). This restrictive habitat provides a useful habitat for wildlife, but it does not specifically focus on catering for a specific species (like a river caters for kingfishers, and a reed bed caters for bearded tits).

However, a rural setting is much more likely to provide a habitat for specific species. For example, there is a coniferous woodland near our house, hence why the wood pigeon population is so high. Our garden is also bordered with a mature hedgerow, providing a safe haven for sparrows, hence why the sparrow population is so high. 

The rural environment is therefore a lot more unreliable. If you do not know the specific landscape features (river, woodland, farmland) it is much harder to predict the species. However, the suburbs are more predictable, as they are all (relatively speaking) the same, providing a suitable environment for more scavenger type birds such as pigeons, magpies and jackdaws, along with the traditional garden birds.

Finally, I made a percentage graph. I personally think that these graphs display the information in the best way. It is quite hard to get your head round at first, but for example: Even though only 2 feral pigeons were seen, 100% of those two pigeons were seen in the suburbs. 

This graph shows that there are 4 species which were in the rural setting but not in the suburbs, and 4 that were seen in the suburbs but not in the rural setting. These therefore cancel each other out (in a sense). We are then left with 7 species common to both locations, and as you can see there is a very equal distribution between the two location on average. 

In conclusion, we can therefore state:
  • Both locations have the same diversity of species.
  • The rural setting is more suited to a specific species.
  • The sub-urban setting has a more evenly distributed species population.