robin's eye. in Romanian it's ciocul berzei i.e. the crane's bill ... interestingly flowers and birds are a glorious 'coincidence' as they offer us utter visual & sound pleasures

I'm glad your bird problem turned out to be seasonal but just in case you ever face this problem again (or any bird infestation problem) I thought it might be helpful to just mention a different angle on this. The problem is not that the birds are pooping (or whatever they're doing) in your pool. That is simply a symptom of your real problem: that your environment is attractive to birds. If you really want to keep birds from being destructive to your property you have to make it so that your land is a place they don't want to hang out on in the first place. There are a lot of different approaches to this but yes, stopping the food supply is one of them. Another would be the mylar balloons someone else mentioned up above. There are also specialized bird scare balloons with 'eyes' that follow the birds wherever they fly as well as holographic tape. These incorporate movement so they are usually more affective than static decoys. There are other senses to attack as well: taste/smell, touch, and hearing. Birds hate methyl anthranilate (a chemical derived from concord grapes that has long been used for grape flavoring)--it gives them a similar sensation to what we feel when we encounter bleach. This comes in commercially available sprays. Also, there are sticky gels, netting, or spike strips that keep birds from roosting on certain surfaces. Lastly, there are sound devices that utilize recordings of predators/distress calls that scare birds away. For a partially or fully enclosed area you could use an ultrasonic device as well (one that can't be heard by humans but is annoying to birds and bats). Make sure that you switch up whatever you use from time to time. If you use balloons, move the location (but always keep it near where the birds are nesting). If you're using a sound device change the interval between effects, try to randomize the effects being used. Also, using the products together in a synergistic way will create a more effective and longer-lasting reaction. I'm glad to hear that no one has mentioned killing or injuring the birds...don't do that. As mentioned before that would be reacting to the symptoms rather than truly solving the problem. Furthermore, it would be very easy to accidentally tamper with one of the MANY birds protected by the Migratory Bird Act of 1918 (and then you'd be in big trouble). Just a side note: be careful when cleaning up the bird poop. Birds can transmit over 60 diseases to humans. Some of them are fatal. Bird dropping particles can be unknowingly inhaled and lead to serious health problems. Good luck in your future bird encounters! Here is a link that might be useful: click for examples, case studies and FAQs about bird pest control

The correct name of that bird is Rock Pigeon (Columba livea). All the populations in the US are feral populations. Truly "wild" Rock Pigeons are becoming quite rare in parts of their natural range (southern Europe, northern Africa and west to India). In the wild, they are restricted to cliffs and mountainous areas, thus the name Rock Pigeon). But they have managed to adapt quite well to the "cliffs" that man builds in big cities (i.e. buildings).

I'd say common grackle. The bill looks too heavy and long for a Brewer's or Rusty blackbird. ETA: One of my blackbird photos for comparison.