We went up to mull for a week last year, and it really was one of the best places I have been in a long time both in terms of wildlife and scenary. In terms of a couple of recommendations obviously there are many many wildlife tours and birding trips but a couple that I would highly recommend:
http://www.discovermull.co.uk/
http://www.turusmara.com/

If your going at the right time of year and can get out to lunga, one of the tresnish isles, it really is fantastic - more puffins in one place than can really be believed, and if you walk to the far end of the island there's a really good sea stack which stands out in my memory because of the number of guillemots (and other birds of course)

The hills/moors around dervaig where good for walking and short eared owl. That said, if you get out into any of the countryside and keep an eye out you've a great chance of seeing something different. The memory that sticks with me is the White Tailed Eagle we saw when walking in one of the glens, we spent a memorable few minutes sat on the ground watching this huge bird flying.

Its a great place to go

Chris

-- Edited by chrisgilbane on Saturday 13th of April 2013 05:00:50 PM

-- Edited by chrisgilbane on Saturday 13th of April 2013 05:01:32 PM

Funnily enough I just got back yesterday from a holiday there, not a true birding holiday but saying that I did get a fair bit done. Most people are interested in trying to get the archetypal White Tailed Eagle shot and most people go on the boat the Lady Jayne, run by a couple from Mirfield of all places and really good fun when I went out on Wednesday. They throw a fish off the back when the eagle comes near and he (as apparently its the male eagle usually) catches it. May take a bit of waiting but I think all the non-birders were satisfied after the eagle spent only about three minutes around the boat. I nearly missed it too! They also stop at interesting birds on the way home so I also got Great Northern Diver, Common Scoter, Black Guillemot and Otter. Well worth it, even if it's a bit on the pricey side. If you don't fancy that there's always watching the eagles from the island itself, the east end of Loch Na Keal is good as is the formalised eagle viewpoint. When we went to the latter we didn't even go in and got both eagle species!

For stuff like Hen Harriers there is no real substitute I don't think for just driving about the island, we found the road between Craignure and Finport was great for them and when combined with a trip to Iona you might also get Corncrake (though we didn't as we're a bit too early). If people are up for a big walk (and towards the top it's pretty icy too) Ben More's a good excuse to bird yielding Shorties and Harrier for us, the former being quite easily found sitting in tussocks! Buzzards are pretty much as widespread as you can get, whilst I never found a reliable Golden Eagle they're quite easily seen on passing and we picked up at least 3 individuals over the week.

Calgary Bay is very nice and non-birders like it as its a beach, but I struck lucky there with Snow Bunting and Rock Pipit, the latter not too interesting but still these were the first decent shots I've had of one. Any of these bays are worth checking early in the morning for passage waders, we were nearer Loch Na Keal and regularly had Greenshank along the shore there. Otter are apparently present on most rocky coastline and people have reccomended various sites but I connected at none of them, instead finding a random set of mother and young somewhere on the south shore of Loch Scridain. We spotted them when driving, so as we went towards Iona we had our attention split between Otters and Hen Harriers! What I would suggest is keeping an eye out for them whenever you're on a rocky beach, they're probably present.

In short we racked up 64 species of bird (including a Barn Owl I missed sitting in the middle of the car!) and a fair few mammals without really making a concerted effort. My highlight though was putting a feeder out by the roadside and getting Yellowhammer on it, setting up a makeshift hide and watching them from dawn. In short, the birding's great and the photo opportunities are there, and I would be very suprised if you didn't connect with at least one eagle species at some point!

Good luck!

Joe