340 The Wilson Bulletin — No. 91 



In my revie\Y I made the f oUowiDg remark : " The flaw the re- 

 viewer would point out is perhaps due to over-enthusiasm on the 

 part of the observers, or perhaps to failure to realize the difficulty 

 of making exact identifications of insects."' Professor Stephens' re- 

 ply contains nothing to offset this impression. I warrant that it" 

 any of the persons concerned in making the studies of the food of 

 nestlings in question will take the trouble to master any group of 

 insects, he will no longer care to risk making specific identifications 

 of small insects that are being fed to nestling birds. 



The detailed nature of statements relating to the food given nest- 

 ling catbirds by their parents is illustrated by the following quo- 

 tation : " Among the 55 beetles fed were recognized may-l>eetles, 

 click-beetles, tiger-beetles, water-beetles, and snout beetles of var- 

 ious species. The flies were mostly flesh flies, though house and sta- 

 ble flies were noted.* 



Professor Stephens gives some explanations, which had they been 

 in the original articles reviewed, would have greatly modified the 

 impression produced. For instance he says regarding the observa- 

 tions on the catbird : " Flies swarmed about and the oD- 



seiwer in the blind could Pee the catbird capture and feed them 

 to the young birds in the nest. A number of these flies were caught 

 and submitted to an entomologist .... who named the flies as 

 above" (p. 158). On this evidence, however, few would card-index 

 the catbird as an enemy of any particular species among these flies; 

 the chance for error is too great. There may have been a score of 

 species of flies among those tlie birds were preying upon, and which 

 particular ones were taken, could not have been accurately known. 

 This instance as explained therefore does not constitute a deflnite 

 . record of catbirds feeding the identifled specie*-; to their young. The 

 paper reviewed, however, unqualifiedly states that among the in- 

 serts fed M-ere house and stable flies. The single instance of a 

 mosquito being fed to the young by a catbird is made clear by a 

 belated explanation, which should have been in tlie original article. 

 It appears tliat a mosquito seen within the blind flew out and was 

 snapped up by the bird. P>nt this does not prepare the way for 

 acceptance of the (>5 records for tlie yellow warliler. as the cir- 

 cumstances could not have l)een tlie same. Fven though this nest 

 was only two feet away, tlie part of a mosquito that might pro- 

 trude from a warbler's bill, in nine cases out of ten. probably would 

 not suffice for certain identiflcation at that distance. 



Would Professor Stephens or his students on the basis of the 

 nestling studies reported care formally to add the name of the cat- 



* Wilson P.ulletin. Vol. XX\'. No. 4. Dec. l!ii;i. ]i]). IT'.t-lSO. 



