ChrisKten
It's true, I quite like Pigeons
The easiest way to observe bird behaviour is to feed birds in your garden... I've been doing this for many hours each day for years. I've posted before about Jay, Crow, Sparrowhawk, and Pigeon behaviour... all of which I see at close range all year round - the Pigeon threads have never been the most popular, but they are often the easiest birds to study. Pigeons are very adaptable and surprisingly (at least to those that see them as Vermin) intelligent - but if the behaviour that I'm about to describe is anything to go by, and if it's not just a sign of illness and/or is in fact common to other species, Pigeons might be smarter than even I imagined.
So, birds hide illness/weakness - probably better than any other animal. Birds can be very ill without showing any obvious (to humans, at least) signs or symptoms... until they're too ill/weak to hide it, which is when it's often too late to help them. Individual birds that are seen regularly, and are unique-enough to stand out from the rest of the flock (maybe one of only a few white/brown/black ones etc), have unique habits - where they go after landing in the garden - favourite perch - where they land on me (only a few favour landing on my head, most prefer my arms and hands) - how easily they access difficult to reach food, etc. So there are individual birds that I can confidently identify.
A known bird that is behaving oddly is likely ill or injured... most obvious sign is when the rest of the birds are spooked and fly off, leaving one bird alone on the ground (although not always, as some birds learn that a neighbour opening a window isn't a threat, so continue feeding as the others fly off). A regular bird that is suddenly pestered by other birds (in the case of Pigeons, males trying to mate with it regardless of whether the bird is a female), or attacked/bullied by other birds, is an obvious sign of illness/injury/weakness. But there's another sign of illness that is more subtle, and is almost impossible to notice... unless you watch birds for hours.
Sometimes a bird will feed with the flock, but not actually feed. The bird will rush to the seed and bend forward to get seed - get to within a fraction on an inch of the seed, but not actually open it's bill to pick up the food. This will be repeated for other seeds as the bird mimics the other feeding birds in the flock. It behaves like the rest of the birds, so isn't bullied - it doesn't stand out from the rest, so isn't more likely to be selected by a predator. So this would seem like a good strategy for a vulnerable bird. But is that what it is, a strategy? Or is it an illness that affects vision and depth perception, preventing the bird from getting the seed?
(I should add that all of the birds displaying this behaviour eventually showed more definite signs of illness later, some didn't survive; so I'm sure that they was ill.)
So, birds hide illness/weakness - probably better than any other animal. Birds can be very ill without showing any obvious (to humans, at least) signs or symptoms... until they're too ill/weak to hide it, which is when it's often too late to help them. Individual birds that are seen regularly, and are unique-enough to stand out from the rest of the flock (maybe one of only a few white/brown/black ones etc), have unique habits - where they go after landing in the garden - favourite perch - where they land on me (only a few favour landing on my head, most prefer my arms and hands) - how easily they access difficult to reach food, etc. So there are individual birds that I can confidently identify.
A known bird that is behaving oddly is likely ill or injured... most obvious sign is when the rest of the birds are spooked and fly off, leaving one bird alone on the ground (although not always, as some birds learn that a neighbour opening a window isn't a threat, so continue feeding as the others fly off). A regular bird that is suddenly pestered by other birds (in the case of Pigeons, males trying to mate with it regardless of whether the bird is a female), or attacked/bullied by other birds, is an obvious sign of illness/injury/weakness. But there's another sign of illness that is more subtle, and is almost impossible to notice... unless you watch birds for hours.
Sometimes a bird will feed with the flock, but not actually feed. The bird will rush to the seed and bend forward to get seed - get to within a fraction on an inch of the seed, but not actually open it's bill to pick up the food. This will be repeated for other seeds as the bird mimics the other feeding birds in the flock. It behaves like the rest of the birds, so isn't bullied - it doesn't stand out from the rest, so isn't more likely to be selected by a predator. So this would seem like a good strategy for a vulnerable bird. But is that what it is, a strategy? Or is it an illness that affects vision and depth perception, preventing the bird from getting the seed?
(I should add that all of the birds displaying this behaviour eventually showed more definite signs of illness later, some didn't survive; so I'm sure that they was ill.)