276 Cleland, Birds of the Pilliga Scrub, N.S.W. [,sf April 



minimal numbers of individuals, of those species to which this 

 method of computation reasonably applies, present in the two 

 milHon acres of the Pilliga Scrub (it being assumed tliat on the 

 whole the rest of the area is not dissimilar to any extent from 

 that traversed). 



If we thus can estimate roughly the numbers of birds of each 

 species in this area, and had reliable data as to their daily minimal 

 rations, as exemplified by the examination of the stomach contents 

 of individuals, we could make out a crude estimate, by multi- 

 plying by 365, of the amount of food consumed by the individuals 

 of each species in a year. If noxious insects were included in the 

 diet, we could say roughly that the birds concerned had destroyed 

 in this area in a year so many of these. I am not, of course, in a 

 position to obtain all the requisite data, but I mention these 

 interesting deductions as showing what possibilities exist for 

 applying the method of bird assessment here presented to prac- 

 tical purposes. Various members of the R.A.O.U. may have 

 opportunities of elaborating it more fully as regards certain areas. 

 Its employment, from the point of view of teaching the public 

 the value of birds, is obvious. 



I propose later to publish in fuU my other data. Meanwhile, 

 the Pilliga Scrub ones are presented as being germane to this 

 contribution. 



In the following enumeration the name adopted in the R.A.O.U. 

 " Check-list " is followed by that given by Mathews in " A List of 

 the Birds of Australia." 



I. Dromaius novae-hollandise {Dvomiceitis novcshollandice'). Emu. — • 

 A flock of seven Emus was seen in the middle of dense scrub on the 

 outward journey, and one bird on the return route. Dr. Jensen 

 saw none. 



6. Leipoa ocellata (L. o. rosince). Mallee-Fowl.— We saw neither 

 the birds nor their mounds, but I was informed that they are 

 occasionally seen. 



10. Excalfactoria australis {E. chinensis aiistralis). Chestnut-bellied 

 (King) Quail.— I did not see this bird, but one of my companions, 

 Mr. Taylor, flushed a " King Quail " at Old Cubbo Station. 



26. Geopelia humeralis (Chrysauchcena h. humeralis). Barred- 

 shouldered Dove. — Several "Squatter Pigeons" were seen near 

 Wangan, specimens being obtained. Mr. Burrow saw elsewhere an 

 occasional bird also. Iris, old straw-yellow ; bill bluey-grey ; 

 pharynx greyish-flesh ; legs crimson lake. No entozoa. 



27. Geopelia tranquilla (G. placida tranquilla). Ground-Dove. — 

 Met with nearly throughout the journey, being flushed from the 

 track as we drove along. Thirty-five were counted over the 189 

 miles. If these birds could be seen and disturbed for a distance of 

 10 chains on each side of the track, this would mean that 35 birds 

 were met with over an area of about 47 square miles, which is about 

 I /66th of the area of the PiUiga Scrub. If uniformly distributed 

 throughout the scrub, and if the above number represents a fair 

 average, then the minimum number inhabiting the whole area would 

 be 35 X 66 = 2,310. If the distance they could be disturbed from 



