Hi Tony, with a 7d you do get lots of noise which starts at ISO 800 you should never be going over ISO 3200 and you can set the 7d to stop at this limit?.
As the nuthatch was perched feeding at the time the slower shutter speed would have worked well, presumably this was taken earlier today when we had some sun or were you in a very shady spot? what time of day did you take it? what len are you are using and what other settings did you have? it may be worthwhile doing a search on line for 7d wildlife camera settings.. All the best Bob