- The very minimum you need is a pair of decent binoculars.
I won't recommend a particular kind, but it is advisable to stick with brands you know. My father uses
Swarovski Optics, I use
RSPB. It is a simple fact that you get what you pay for, and you should buy what you can afford. Speak to a specialist dealer when selecting, then consider buying specific models online - ex-birders sometimes sell their gear at silly prices.
Joining the BTO sometimes gets you a free pair of binolculars, and some birding magazines sometimes offer binoculars as an incentive to subscribe - check what offers are available.
- A spotting scope and tripod are as important as binoculars, because of the greater magnification and steadier view. Again, you get what you pay for - I use a second-hand Opticron scope. New scopes can cost as much as £3,000 ($5000).
If you want to get into birding in general, with seawatching as an aside, spend as much as you can on binoculars, then see what you can afford for the scope after that. Some dealers will do you a deal if you buy bins, scope and tripod all at once. Consider service as well - Swarovski optics are among the most expensive available, but they will often repair registered owners' equipment for free (my dad uses Swarovski - his tripod got dust in the mechanism in the Gambia, Swarovski said "send it in, we'll clean it, no charge").
- Bird books. Don't go by price, go by content. You need at least decent national guide, plus a book on identification by behaviour would be useful. Check online bookshops and ebay, but, if you can afford it, I always recommend buying from a bricks-and-mortar local bookstore - you cannot beat the helpfulness and intuitive advice of an actual human being.
My personal bird books are:
I also read
Birdwatching magazine (link is an advert), and sometimes
Birdwatch magazine.
You may not recognise a bird straight away, and it surprising how much detail does not stick in the memory. Notes and sketches will be invaluable to later identification, no matter how badly drawn (they're only for you, after all). You will probably also end up creating a life-list, year-list or site-list, so will want to record the dates, times and conditions you see each bird.
Not so important, but you may want to snap off record shots for later identification.
You are going to be standing still, beside the sea, in many weathers. A decent long coat, hat, maybe gloves will all be useful at some point.
Seawatching can take hours, so some people like to sit down with their tripod lowered to be used from a camp chair, with a flask of
hot coffee to hand. I recommend using an "unbreakable" stainless steel flask, in case it gets kicked off a cliff. Sitting down can also make it easier to take notes. It is possible to buy special
folding hides that include a chair, or you may use a fishing tent or
fishing umbrella.
Dictaphone - to record observations without having to take your eyes off the birds. There is at least one model designed to fix to your binoculars.
MP3 or MP4 player - it is possible to buy
recordings, digital stills and video clips of the birds you are likely to see.
Camera mount for your tripod - many birders are getting into
digiscoping - taking digital photos through their spotting scopes. It can be an expensive hobby.