Advice for making new shed bird-friendly

Hi.  I am planning to build a new woodshed this summer and wondered if anyone had any specific advice or facts that I could incorporate into the design?  I'm at the very start of the design stage (the groundworks don't happen until April) so I am gathering elements now.  The dimensions are not set but it's likely to be about 12m long, 4 or 5m wide and of proportionate height (?).  I want to make it reasonably high and with pronounced eaves to try and attract swallows.

Internally there will be swallow ledges high up but am interested in hearing from anyone who has undertaken a similar project and incorporated bird-friendly design elements.  The two other species I would love to attract - Holy Grail ones for me - are barn owls and swifts, but I hear that's not easy.

Any advice/links gratefully received.