@paulhenry3443 - My experience with birdwatching has taught me that holding 10x binos steady on  a windy day can be difficult when looking at birds.  I would suggest the 8x.  I think 8x42 offer the best in terms of looking for birds.  The rule of thumb is to spend as much as you have in your budget. A lot of the more expensive binos help you see in low light (dawn or dusk).  One factor is the "eye relief", if your brother wears glasses you will want a longer eye relief so he can use them with his glasses on.    Another factor is the "close focus", how close can you get to the object you are look at.  A shorter close focus is helpful when looking at butterflies, bees, and invertebrates.  I hope this helps. 

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