Ayrshire and south-west Scotland is rich in wildlife and Craig Tara makes a great base for exploring and hopefully seeing it. Obviously some sightings are restricted to parts of the year (e.g.
don't expect to see Swallows in winter!).
This page gives some examples of what is on offer with links for more details.
Ayrshire is a large county with varied habitats that make for good birding at any time of the year. Adjacent to Craig Tara is Doonfoot which is great for waders, gulls, and waterfowl. In recent years it has had more than its fair share of rareities, especially during migration. Other major sites in the area are Maidens beach, Irvine harbourside, Martnaham loch (just outside Ayr). These and many more are covered in the Ayrshire Birding website: one of the longest running, active, local birding web sites. It covers the best locations, has lots of photographs, articles and information to help the visiting birder.
A recent survey at Culzean Country Park found a total of seven species of bats including Nathusius' pipistrelle and Leisler's bats. The long coastline (especially north of Craig Tara) is great for watching seals. The best time is at low-tide when they haul out to rest. Another good spot is Troon harbour which usually has a few individuals waiting for scraps from the fishing boats. Otters are present on lots of Ayrshire lochs and rivers - but seeing them is a matter of patience and extreme luck. Similarly, it is possible to see pods of Dolphins feeding in the Firth of Clyde: a high vantage point such as the Heads of Ayr next to Craig Tara is ideal and improves your chances of seeing them (a bit). To see Red Deer you'll need to tackle the higher ground in the south of Ayrshire (see the article on Walking near Craig Tara for suggestions).
The less developed south of Ayrshire is particularly good for flora, and the best sites are typically protected as reserves managed by the Scottish Wildlife Trust. For example, Grey Hill Grassland near Girvan has many rare plants; Auchalton Meadow is good for orchids; while Feoch Meadows near Barrhill is a botanically-rich mosaic of dry and wet grassland, fen meadow and mire.
In spring the Heads of Ayr near Craig Tara is one of the first for Primroses while the River Doon is a carpet of Bluebells and Snowdrops.
In Autumn, the broadleaf woodlands of the Failford Gorge (near Tarbolton) and Ness Glen (see Walking section) are a riot of colourful leaf displays that easily rival New England. These areas are also excellent for fungi-hunters.
The best sites for butterflies in Ayrshire are the same ones for the best flora - especially coastal sites in the south. In recent years more southerly species such as Wall and Comma are making advances northwards.
The Butterfly Conservation Trust has developed a butterfly reserve in the Mabie Forest near Dumfries which would make an excellent day trip especially when combined with some of the SWT reserves in the area.
In addition to the extensive network of SWT reserves, the RSPB has several in the area. Lochwinnoch (near Beith) has a visitor centre and a network of paths around its mixed habitat. However, for sheer spectacle, the famous Aisla Craig off Girvan is a must during the spring and summer when huge flocks of Gannets fill the air. Other species such as Puffin, the other Auks and Manx Shearwater are also present. You can tour the island (landing is wind-dependent and awkward) by small boat from Girvan or take the regular summer trips on the steam ship Waverley.