Above is a photo that I shot today and I am pretty happy with it. I was able to crop the image heavily, but it still looked ok. The image was shot with my Tamron 70-300mm lens and I was kinda close but with the cropping during post-processing I could come up with the result above. In Germany we call the bird “Kohlmeise” but the English name is kinda funny because you guys call the bird “great tit” but the scientific name is “Parus major”. I am pretty proud because my bird photo collection grew a lot over time. I bought my Tamron 70-300mm back then because I hoped I could get closer to these birds but I was not sure. But it works with 300mm, you just need to learn how to sneak up (laugh).
Diary of Dennis 
Walking quietly and not saying anything really makes a huge difference!
That’s true. Birds also don’t like it if you do erratic movements, so I featured out over time when you approach them very slowly it can help too. Some birds are not afraid when you walk slowly. Having a brown/green hunter t-shirt or something like that works pretty well too. Luck is also involved, some birds let you come close within the 300mm range, other are more shy and fly away before you take the photo. I like this type of photography, because you need to slow down in the nature to take these photos, and that is good for the mind. 🙂
I think I got some experience with this and might write a post about how to get bird photos with medium focal length, because there are some tricks that work.