^°'i^2?" ] CLELAXD, Takhuj a Bird Census. 19 



rised the (jhservations so far made. As pointed out in- others 

 during the discussion, not only is a crude idea obtainable in this 

 way as to the numbers of our birds, but by recording results 

 at the present time and making the same journeys again after, 

 say, some years' interval, some idea might be obtained as to 

 whether any species was decreasing markedly in numbers, hold- 

 ing its own, or increasing. What interesting results might not 

 be obtained a century later ! 



In my previous paper, which should be consulted, I have indi- 

 cated clearly how the type of vegetation necessarily affects the 

 extent of the lateral view during the journey. Simibrly the 

 size of the bird and its habits, such as not being easily disturbed 

 or vice versa will modify materially the distance from the road 

 at which it can be recognised. Thus, as regards certain species, 

 such as ]\Iagpies, and Black-and-White Fantails, easily recog- 

 nisable or continually on the move, the results recorded in my 

 tables probably approximate very closely to the actual numbers 

 present in the area under review, whilst in the case of other 

 kinds, such as Tree-Tits {Sniicrornis) and White-plumed 

 Honey-eaters in the tree-tops, the numbers actually seen are 

 doubtless merely a tithe of those which escaped notice. I have 

 given, however, data as regards all birds seen, and Ave can say, 

 as regards the figures, that at least these numbers were in the 

 area and in many cases probably very many more. 



The question may be asked as to the reliability of the identi- 

 fications. I can lay no claim to infallibility, and am perfectly 

 aware that in my returns some mistakes must have occurred. 

 I have, however, avoided these as far as possible, and when in 

 doubt have expressed this either by a question-mark or by re- 

 cording the genus only, or by merely noting the birds seen as 

 unidentified. Even with these precautions, however, some wrong 

 identifications have probably been made. 



As regards the mode of progression, driving in a buggy or 

 motoring give apparently about the same results, though the ad- 

 vantage is slightly in favour of the former as more time is al- 

 lowed for observation. When walking, the number of small 

 birds keeping to the trees is increased, as the trees can be care- 

 fully scanned, whilst birds calling can be searched foi. Some 

 means of progression is, of course, necessary so as to avoid 

 counting the same birds again, and with the same object m view 

 the track of the journey must not interlace. I have, however, 

 in this census considered a return journey over the same groimd 

 as two journeys, and have labelled such second iourneys (a) 

 and a rare third journey as (b). The object has been to test 

 the reliability of the method. Clearly, if the birds had not left 

 the neighbourhood of the route followed, one .should see the 

 same individuals on each occasion if conditions were ideal. My 

 full tabulated list shows that in such return journeys the num- 

 bers of species seen and the numbers of individuals of these ob- 

 served do approximate fairly well on the whole with each other 



