In [1]: data = [
   ...:     {'id': '10', 'animal' : 'cat'},
   ...:     {'id': '11', 'animal' : 'dog'},
   ...:     {'id': '3', 'animal' : 'pigeon'},
   ...:     {'id': '10', 'color' : 'yellow'},
   ...:     {'id': '11', 'color' : 'brown'},
   ...:     {'id': '3', 'color' : 'grey'},
   ...:     {'id': '10', 'type' : 'furry'},
   ...:     {'id': '11', 'type' : 'fluffy'},
   ...:     {'id': '3', 'type' : 'dirty'},
   ...: ]

In [2]: from collections import defaultdict
   ...: ids = defaultdict(dict)
   ...: for d in data:
   ...:     ids[d["id"]].update(d)
   ...:


In [6]: list(ids.values())
Out[6]:
[{'id': '10', 'animal': 'cat', 'color': 'yellow', 'type': 'furry'},
 {'id': '11', 'animal': 'dog', 'color': 'brown', 'type': 'fluffy'},
 {'id': '3', 'animal': 'pigeon', 'color': 'grey', 'type': 'dirty'}]