First Year... First Photos

My kids got me involved with them this year for the first time in "Bird Watch". We went out and bought a feeding station and were amazed at how many and how often the birds visited us during the day. It has become part of our routine now to set out food each morning. With the feeding station close to the house it gave opportunities for some photography too. My standard lens was rubbish so I invested in a 150- 600 zoom lens and it just took my opportunities to a whole new level. I am not in any way an expert but I am learning and would appreciate any hints or tips to improve my photos. I have attached a few that I have taken so far.