A common sight here on the museum’s campus is the red-shouldered hawk. This one is fluffed up against the cold as it perches on a branch while surveying the swamp below for movement. Birds often fluff themselves up in cold weather, trapping air between the feathers effectively raising their R-value.
Our resident red-shoulders are fairly tame, that is, they’re quite used to people. I’ve walked past them at a distance of less than ten feet without causing alarm. You could could do the same, and may already have done so without realizing it.
I would caution against making loud noises, jumping up and down and waving your arms if you want to get close to one of these birds. No, just keep a slow steady pace as you walk along the paths and chances are any nearby hawk will ignore you, for the most part (one eye will most surely be tracking you).