First, you'd need to upoad the photo.
Try to give a meaningful name and include some details in the description, as below.
Then, the easiest way would be to copy a fragment from another page and change the details.
also, Help:Adding a photo to a bird entry - BirdForum Opus
If you've ever edited a wiki, it's similar. You should be able to do all of the above without having any additional permissions.
Login required - BirdForum Opus
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File:Santa-Marta-Blossomcrown Female CBALN.jpg - BirdForum Opus
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Then, the easiest way would be to copy a fragment from another page and change the details.
European Robin - BirdForum Opus
www.birdforum.net
If you've ever edited a wiki, it's similar. You should be able to do all of the above without having any additional permissions.