Have non-overlapping and sometimes complimentary distributions. Found in different portions of the same geographic area. Within-habitat segregation . The same area in the same habitat are used differently. Different species of tits spent differing amounts of time in different aspects of the habitat.
Birds can also segregate themselves temporally .
Since the breeding season is the most potentially stressful time of the year, let's look at breeding times. And something similar is true for species all over the world. The interesting thing is that the breeding season of the entire avifauna of a geographic area is about 1.35x the average season of the component species. In other words, add up all the breeding lengths of all species - some nest over a period of 6 weeks and some nest over a period of maybe 3 months. Take the average of these and multiply that average by 1.35 and you'll come up with the total time over which all the birds in that area breed.