Once cured, any brand should be safe around birds. Silicone is non-toxic, but of course, not good to eat since it is indigestible. While curing, birds should be kept out of the area.
For silicone that will be used in aquariums or vivariums, you want to specifically look for pure 100% silicone without mold inhibitors or other chemical additives, since they could leach into the water and harm your fish or frogs. GE I silicone is the brand and type I was recommended to use on my frog tank.
GE All Purpose Window and Door Silicone 1 sealant is a 100% silicone and 100% weatherproof caulk that is ideal for areas that could be exposed to harsh weather conditions. Its same-day rain-ready formula
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There are also brands that are marketed specifically for use in aquariums or vivariums, but they usually come at a significant price markup for the same thing. Regardless of the brand, you must keep pets away while the silicone is off-gassing. It has a strong odor until it finishes curing and the fumes could be harmful. Once it has cured, it is safe and chemically inert.
Personally, I would just buy whatever product is recommended for your home project, since it is not being used inside an animal enclosure and the white silicone usually matches windows better than clear or black. Mold inhibitors should not be a significant concern ... and they will help to prevent mold which is a potential health risk for birds, too. But if you are worried about extra chemicals, look for 100% silicone and use it with confidence.