Over here is a list of useful links that you should visit! Many of these websites also suggest and recommend gears that are suitable to and other genres of photography.
Besides these links, do explore youtube for gear review and discussions. Afterall, wildlife photography is not all about heading out into the field to shoot the birds, it is also about upskilling, learning new techniques and finding out what subject you are most passionate about! Above all, you should also pay attention and learn about the animal's behaviour and characteristics. This way, you will also gain some new knowledge as you are doing what you love. Find out more about the animal's behaviour to better shoot them from the websites under 'Wildlife photography sites'!
Scenario:
Sunbirds are skittish and timid birds, if you go too close, they will fly away! Knowing the bird's timid character will reduce the chance of scaring the bird away and missing your shot!
For gear reviews:
For discussion
For second hand goods(sale and purchase):
Wildlife photography sites
Nature TLL (Learn How to shoot different kinds of animals)
Outdoor Photographer(Check out the tips and techniques shared here)
Singapore Wildlife