For someone who has always loved goldfinches, I never knew we had them just around the corner in my local patch! A flock of 6 individuals in the bushes chirping away!
They remind me of a dartboard for some strange reason... the red stripe on their faces, and the yellow streak on their black wing like a dart- anyone else the same? Apparently not, as through my research I found that Goldfinches appeared frequently in medieval paintings of the Madonna and Child as a symbol of fertility and resurrection! Unfortunately, this fixation on their amazing patterned feathers led to goldfinches were widely kept as cage birds from the wild in the 1800's, but it was due to the RSPB's hard work that the government passed an act to make the sale of wild birds illegal in 1933.
These populous birds (Green Listed) are amazingly adapted. Their beaks are perfect for removing seeds for food, allowing them to access seeds that other birds may not be able to access as easily, so they are one step ahead of the game when it comes to food. Goldfinches nest in shrubs but prefer trees, especially fruit trees, and use moss, lichen, roots, grass with wool and hair to form their nests.
However, whenever I think of Goldfinches, I always think back to Darwin and his theory of natural selection. Studies based on the Galapagos Islands led to the identification that finches on different islands among the Galapagos had differently shaped beaks. The conclusion was that these finches had spent so long isolated on the islands, that through generations of finches, their beaks had adapted (through natural selection) in order to survive off the food source on their island, as each island had different ecosystems that would require different builds of beak to access the seeds or insects. This is a structural adaptation.
Natural selection is the idea that organisms adapt over time to fit with their environment and the changes in their environment in order to survive. The individuals of the species with the most desirable characteristics are able to produce the best-adapted offspring. This way, those individuals survive as are the strongest suited to the habitat and those who don't adapt die and may become extinct as they are poorly suited. In this case, the finch individuals with the best beak for extracting the seeds available on the island passed on these characteristics in their genes, and over time this eventually formed a new feature the finches were born with.
This diagram perfectly illustrates how the Galapagos Finches evolved to each island's habitat, with a beak each perfectly suited to survive off what the island has to offer. However, it's not only biological features that can adapt, but behaviours too! This is behavioural adaptation.
One particularly interesting finch that has changed it's behaviour is the Vampire Finch of the Galapagos Island. They live on the Darwin and Wolf islands which have scarce resources of seeds and insects, and these Vampire finches have evolved from the Sharp-beaked ground finch in order to survive on these short supplied islands.
The Darwin and Wolf islands also have Blue-foot Boobies as visitors, but for the ravenous Vampire Finches they are...well...dinner!
Originally evolved from Sharp-beaked ground finches, they use their sharp beak to peck at the feathers and skin to reach the Blue-footed booby's blood, and then drink the highly nutritious blood. You would think the Boobies would have some objections, but it is thought the Boobies don't mind as the finches originally developed a mutualistic with the Boobies by pecking them to remove the fleas and parasites from their feathers, so that way the Finches benefited and so did the Boobies.
However now, this is Vampire Finch commonplace behaviour even if there aren't any parasites and draw blood from the Boobies for the blood's nutrition- and the Boobies haven't caught on yet!
Behavioural adapatations also come in the form of migration. For example, the Eurasian Woodcock has migrated to the Irish Coast for centuries and is so 'on time' each year that it has even written it's way into Irish Folklore, but the routes, timings and prompts for their migration are unknown! Its safe to say we are still learning about the evolution of certain species, and it's not always as simple as they migrate because its warmer down south!
This is a prime example of nature's ability to adapt and evolve its behaviour to be able to survive, but one thing unfortunately nature is yet to evolve and adapt to survive through is human activity.
We can together try to live a more sustainably in order to give nature a chance of thriving, so visit 365actions.org where daily articles are published with actions on how to adapt and change YOUR behaviour to help the environment, and I recently contributed with action 048- 'Avoid buying cut flowers'.
Nature never ceases to amaze me, so next time you see a bird, have a think about what incredible adaptations the species has undergone to be able to be perched right in front of you!
Outdoorsy Anna