The Pelican Bird is on the bottom because it's traits are COMPLETELY different from the rest of them. It lives in different areas and spends time with different bigger birds like the Ospray.
The Finch being next because it's trait are a little off the Cardinal, Robin and the Blue Jay. It is smaller and comes out in only specific times of the year.
The Cardinal is also next because it is a single bird type. It stays alone but with one female at all times possible to protect the female. Especially if the female is about to lay eggs.
The Robin is a classic bird. The Robin stays with family as well as the Cardinal. The male stays with the eggs and the female goes and gets food and when she gets back, she will feed the babies.
The Blue Jay is the biggest out of the Finch, Cardinal and Robin. It is know for its cat meow like call, not to be confused with the Cat bird. The Blue Jay lives in all kinds of weather but mainly in colder weather.
Hope this Helps! :)