#1 Get Outside Early The number one thing you can do to improve your bird photography is to make/create your images within two hours after sunrise. The light is the best then, soft and warm yellow tones and the birds are their most active. If you can't make it outside that early, you could shoot the two hours before sunset, the birds won't be as active, and the light will be a little more orange or red tones. Light in photography is so important that this one simple thing can turn a good photograph into a stunning photograph.
#2 Push The ISO
I don't like Luminance noise or graininess in my images. But, if I have to I'll push the ISO up because a grainy image is better then no image and a sharp image is better than a blurry image. So a sharp grainy image is better than no image too. Also, if you print an image or you post it online, the noise is never as bad as it looks at 100% in Lightroom or Photoshop. Can you tell this was at 3200 ISO?
#3 Get Eye Level
The Point of View is so important, getting eye level makes it easier for the people to connect with the image, you can also manage the background by moving up or down and right or left.
These seem like very easy simple tips, but it's sometimes difficult to get up early enough, it's hard to change the ISO when you know you're adding noise, and it can be hard to lay down on the ground to get eye level. But the results speak for themselves. Practice these this weekend if you have a chance, and let me know how it goes.
Enjoy! Thanks As Always Tim