Posts

Pecking Order – the hierarchy at the feeders

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Bird feeders act as central congregation points for local birds, but when they start panic buying, which species is top of the pecking order?
A study carried out by the University of Exeter and the BTO suggests that heavier birds are more dominant at bird feeders, allowing species such as House Sparrows to gain superior access to higher “value” food that is either high in energy or efficient to consume (e.g sunflower hearts require less energy to eat than a sunflower seed with the husk still on).

This idea of dominance was calculated by recording which of two feeders a bird visited (either a “low value” sunflower seed with husk feeder or a “high value” sunflower heart feeder), the length of time a bird spent on the feeder, how many pecks a bird made whilst at the feeder and the outcome of any interactions between birds of different species (i.e. would a House Sparrow displace a Blue Tit from a feeder?) The ten species involved in the study, ranked by dominance were as follows: House…

Bird Migration – Navigation

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Coming into spring, with the first few Swifts arriving in the UK in the last week, this seems like an opportune moment to discuss how birds navigate in order to migrate. Whilst the feat of a tiny Willow Warbler travelling 12,000 km (in the case of Phylloscopus trochilus yakutensis) is humbling and physiologically incredible in its own right, migration becomes even more fascinating when you consider how the birds navigate, without the luxury of GPS, Google Maps and all the other tools humans need to find their way around.

It is thought that some birds use the Sun to navigate whilst there is also evidence that points to Homing Pigeons using olfactory cues to navigate, building up a local “map” based on odours at each location. However, we can’t explain navigation without considering the cognitive abilities of birds and their ability to build mental maps.

Perhaps the most remarkable way this is done is using the Earth’s magnetic field. Juvenile birds of some species on their first migrat…

I'm in Tallinn!

Ham Wall 25/3/17: Grass Snake, Glossy Ibises and Bitterns

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After a busy few weeks, it was good to get outside at the wonderful RSPB Ham Wall in the Somerset Levels.

The day was unseasonably warm, but the wind was distinctly chilly, especially in the Avalon hide, which seems to have been designed to be cold and blustery! Spring was definitely in the air, with a flock of 20+ House Martin and 10+ Sand Martin going over our heads at Viewing Platform 1. Chiffchaffs were calling pretty much all the way from the car park to the Viewing Platform, where there were also all of the common duck species: Wigeon (still here from Winter I suppose), Teal (ditto), Mallard, Tufted Duck and Shoveler, with a few Gadwall and Pochard also there. Coots and Moorhens are easily overlooked, but seem to love making a cacophony of noise in their many scraps.

The Avalon hide, in all its blustery glory, was hugely productive. In the space of around 30 seconds, a Bittern made a short flight right in front of the hide, two Marsh Harriers flushed the ducks off the water in …

A Fantastic Male Sparrowhawk!

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Hello all,
This week saw some great birds in the garden, with Long-tailed Tits, Chaffinches and the usual suspects in high numbers too. There was a more special visitor too, though...

A fantastic male Sparrowhawk flew across the garden, landed on a piece of decking before coming back to perch in the tree. That branch, however, is less brilliant!

 Once again, there have been Short-eared owls at Uphill, with three being seen throughout the week. They are large birds, with a wingspan of around a metre, which makes them Britain's largest common owl species. They favour areas of coastal scrub and are diurnal, but show best shortly before dusk. There are certainly better pictures elsewhere on the internet, but below are some of my efforts, one of which was digiscoped from about 100m!                      


This bottom one clearly isn't a short eared owl; it's Ed and me making an appearance on Winterwatch after they got in touch with us to enquire about the results for our coloure…

House Martins

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Hello all,
First off are the House Martins. When I visited a friend's house recently, we discovered that one of the nests was still in use on the side of his house. This provided us with some excellent photo opportunities; some of the results were better than others. With many of the photos, I found myself thinking "this would be fantastic if the House Martins weren't flying past the nest at 40mph!" Not all were meaningless blurs, however...

It's fantastic to see these Summer visitors back after having made such remarkable journeys.



George Rabin

What's a bird's favourite colour?

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A shortened version of the project write-up can be read here!

Abstract
This was a field-based experiment to attempt to answer a question: Do birds have a favourite colour? Four coloured feeders (dark blue, green, yellow and red) and a clear control were used. The number of visits and the mass change in the feeders were recorded so preferences could be gauged. The results show a clear trend for blue being the preferred colour; red and yellow were unpopular. We suggest that this is because high energy colours (blue and UV) are used by birds in short distance communication and that the blue feeder may have been the most detectable for the birds. We also suggest that red and yellow were unpopular because they are employed for aposematic colouration (toxins) in insects.
Applications of this research could include influencing the design of turbines or aeroplanes, to deter birds. 

Over 3000 feeder visits later...






George Rabin & Ed Thurlow