wow, 1/13? was that hand held? if so, good job!....for the future if you can keep your shutter speed up, that is really preferable, especially with birds, moreso with birds in flight. a typical shutter speed to shoot for if handheld is the inverse of your focal length, so at 250mm, you'd want to try and be around 1/250s usually its preferable to raise the ISO to whatever you're comfortable with, its easier to deal with some noise rather than camera shake blur which will be an issue at the telephoto ranges used for wildlife, it'll help raise the number of usable images you can get.
my personal settings for wildlife are to shoot in manual mode, I typically set the aperture to the level I want for DOF or lighting circumstances where I'm at (it usually ends up being wide open most of the time, sometimes stopped down a stop or 2 if the lighting is really good), then I set my shutter speed for my subject (for birds I like at least 1/800 (depending on the lens), better up around 1/1600-1/2000 for birds in flight, if I can get there with the lighting), then I turn on auto-ISO with a range of 100-2500 (which is what I'm comfortable with on my body, different camera bodies will handle raised ISO differently, just use what you're comfortable with) to handle any slight lighting variations between shots so I can concentrate on my subject. there are many other ways to do it, but this has worked well for me.