BUBO's Targets feature is a handy way to identify the species you've not seen that have been seen by the largest number of other birders. For those of us who are family listers, the data held within the BUBO database can also be used to identify our most glaring family gaps... and those families which are the trickiest.

The easiest five bird families to see are fairly predictable. Top of the list are the ducks, geese, and swans (Anatidae) followed by kites, hawks and eagles (Accipitridae), herons and bitterns (Ardeidae), pheasants and allies (Phasianidae) and pigeons and doves (Columbidae). These are all near-cosmopolitan families and even a short burst of birding anywhere in the world would likely result in at least one member of each of these families being seen. The fact that they're all non-passerine families indicates perhaps that there's a source of bias in the data, caused by listers creating a BUBO list and getting bored long before they enter everything they've seen. The first passerine family, the thrushes (Turdidae) comes in at number 17, and the next four are the finches and euphonias (Fringillidae), swallows and martins (Hirundinidae), starlings and rhabdornises (Sturnidae) and chats and Old World flycatchers (Muscicapidae). All again are widespread families containing many common species. In total, there are 54 out of the world's 252 extant bird families which at least 75% of BUBO listers have seen at least one member of.


What about monotypic families, those unique branches of the avian evolutionary tree which are always a major target on a world birding trip? Almost 80% of BUBO listers have seen an Osprey, not surprisingly given its near-worldwide range. Bearded Reedling has been seen by nearly 70% of listers, reflecting the fact that many of BUBO's members are based in Britain. Following a long way behind are Hamerkop (43% of listers), Wallcreeper (38%) and Limpkin (37%). Hoatzin, the most isolated monotypic family on the evolutionary tree, is way down in 174th place, seen by fewer than 19% of listers.

There are some major families which are a long way down the list. The tyrant flycatchers and hummingbirds are in 78th and 79th place, with only 60% of listers having seen members of these families. Antbirds are in 126th place with only 37% of listers having seen one, only just ahead of much less speciose Neotropical families such as cotingas, tinamous and jacamars.

Among the most difficult families to see, some of those monotypic families feature again: Kagu of New Caledonia, the Asian Przevalski's Finch and Sapayoa of South America have been seen by only around 2% of listers, and it's no surprise that four New Guinea families are among the ten least-seen. The “most difficult” though, is perhaps a surprise: the chat-tanagers of Hispaniola, seen by only a little over 1% of birders. Two other Hispaniolan families, Palmchat and Hispaniolan Palm-tanagers have also been seen by under 4% of listers, perhaps unexpected given how easily accessible these birds are in the Dominican Republic, an inexpensive destination to visit.