The buzzard was found in the Dulsie area near Nairn on Sunday March 15.
The birds of prey make the journey back from Senegal to Glenogil in Scotland to breed each year.
The number of survey sites in Scotland reporting red squirrels remained between 51% and 52%.
Trees for Life will establish the centre on a 10,000-acre estate in the Highlands after receiving more than £2m in funding.
The fabric slings and pouches help injured animals feel safe as they recover.
Scottish SPCA was contacted by a local vet after the animal was found on Monday morning.