How many birds do we see?

I have started a little project a few weeks ago. More precisely, I have started a project with a small goal (hence my calling it “little”) but with a long, long way to get there.

I want to know – just roughly – how many birds I have seen in my life. Not how many bird species, but how many bird individuals.

In order to achieve this, I have started to “digitalize” all my notes and various travel reports, which is no small feat. I reckon that this will keep me busy for at least a year, but one of the project’s most critical aspects has recently led to an interesting insight, which I feel is worth blogging about. 
The critical aspect is this:
I will only find out how many birds I have counted and written down. However, this may be way, way below the number of birds I have actually seen but not actively noted: from the car, walking to work, in front of my office window and so on. But just how “way, way below” the actual number will my data’s overall sum be?

I have no idea!

In order to shed some dim light onto this dark figure, I painstakingly wrote down every single bird I saw during a recent visit to the Wagbachniederung, a very attractive wetland complex (former poo ponds) near Heidelberg. The Wagbachniederung is reknown for its waterfowl, shorebirds, and good breeding populations of several species that are very localized in Germany. During such a visit, one would normally just write down the numbers for the “better” duck species, for all the shorebirds, and for a few selected songbird and raptor species. The rest would be uncounted and not put down in the notebook.

A classic Wagbachniederung scene: reeds, water & ducks (Gadwall, Shoveler, Teal, Pintail, Common Pochard, Mallard)

So, this time I counted the common species – one by one – with the same verve as I would apply to the area’s “specials”, and the results are remarkable. Below is a long, long list of the species I encountered (66, which is a very respectable species count for the middle of March in southern Germany) and the totals for each species. Species in bold are species I would have counted and written down as “special” in my notebook – and that would thus have been included into my species statistics mentioned above.

1. Great Crested Grebe – 3
2. Little Grebe – 10
3. Black-necked Grebe – 5
4. Cormorant – 76
5. Grey Heron – 2
6. Mute Swan – 48
7. Greylag Goose – 48
8. Bar-headed Goose – 1  (escape/feral)
9. Canada Goose – 18
10. Egyptian Goose – 1
11. Mallard – 88
12. Gadwall – 492
13. Pintail – 3
14. Shoveler – 21
15. Teal – 70
16. Garganey – 5
17. Red-crested Pochard – 3
18. Pochard – 54
19. Tufted Duck – 44
20. Goldeneye – 2
21. Goosander – 1
22. Goshawk – 1
23. Common Buzzard – 6
24. Pheasant – 3
25. Water Rail – 3
26. Moorhen – 1
27. Coot – 99
28. Little Ringed Plover – 1
29. Lapwing – 1
30. Black-headed Gull – 7
31. Yellow-legged Gull – 2
32. Woodpigeon – 19
33. Stock Dove – 6
34. Black Woodpecker – 1
35. Great Spotted Woodpecker – 2
36. Barn Swallow – 1
37. Meadow Pipit – 1
38. White Wagtail – 6
39. Winter Wren – 5
40. Dunnock – 4
41. Eurasian Robin – 2
42. Eurasian Blackbird – 5
43. Fieldfare – 297 (very strong migration)
44. Song Thrush – 4
45. Mistle Thrush – 2
46. Chiffchaff – 1
47. Firecrest – 1
48. Blue Tit – 13
49. Great Tit – 22
50. Long-tailed Tit – 12
51. Nuthatch – 2
52. Short-toed Treecreeper – 1
53. Great Grey Shrike – 1
54. European Starling – 49
55. Jay – 2
56. Magpie – 5
57. Carrion Crow – 13
58. Eurasian Tree Sparrow – 178
59. House Sparrow – 15
60. Chaffinch – 15
61. Hawfinch – 1
62. Serin – 1
63. Greenfinch – 12
64. Goldfinch – 8
65. Bullfinch – 3
66. Reed Bunting – 7

If I haven’t messed up above, the overall sum should be 1,816.

A fine adult male Goshawk where you scarcely ever see it – perched on reeds after an unsuccessful waterfowl hunt

As a purely “recreational” birder, who only writes down what is personally interesting, the sum would be 30, or 1.6% of the individuals present at the time of my visit.

Just 1.6% !

And if I was more thorough and e.g. conducted a complete waterfowl survey, the sum would be 1,115 or 61% of the individuals present at the time of my visit.

This still means 40% of the birds in a given area would go unnoticed or rather unnoted by me even on “counting days”.

Whatever the outcome of my “little project” of counting all the birds I have seen in my life will be (probably in the – very – low Millions), it seems safe to assume that this number will be no more than 50% of the amount of birds I have actually laid eyes upon in my life.

Which, I guess, is nice to know.