SAFETY DEVICES IN BIRDS ' WINGS — GRAHAM 305 



Some flight character isiics — Continued 



Little owl... 



Jay 



Lapwing 



Black-iieaded gull... 



Kestrel 



Partridge 



Chough 



Moorhen 



Domestic pigeon 



Woodcock 



Teal (cock) 



Common gull 



Red-legged partridge 



Rook 



Short-eared owl 



Wood pigeon 



Shoveller duck 



E. little bustard 



Grouse 



Great crested grebe.. 



Curlew 



Willow grouse 



Pheasant (cock) 



Heron 



Blackcock 



Griffon vulture 



Weight 

 (ounces) 



6.00 

 6.00 

 6.50 

 7.00 

 7.75 

 12.00 

 12.00 

 12.00 

 12.00 

 12.00 

 13.00 

 16.00 

 16.00 

 16.00 

 16.00 

 18.00 

 20.00 

 22.00 

 23.00 

 24.00 

 29.00 

 30.00 

 38.00 

 40.00 

 40.00 

 260.00 



Wing 

 loading 

 (pounds 



per 

 square 



foot) 



1.02 



1.03 



.57 



.63 



.96 



2.00 



.76 



1.43 



.95 



1.24 



1.96 



.85 



2.50 



.98 



.76 



1.48 



2.50 



1.46 



2.23 



3.50 



2.00 



2.85 



2.40 



.92 



2.56 



1.85 



Span 

 loading 

 (ounces 

 per foot) 



3.67 

 3.52 

 2.90 

 2.47 

 3.72 

 8.50 

 4.64 

 6.75 

 5.00 

 6.00 

 6.40 

 4.50 

 10.00 

 6.30 

 4.80 

 8.00 

 8.00 

 7.70 

 11.50 

 9.60 

 9.20 

 13.30 

 19.00 

 9.10 

 15.40 

 31.00 



Span 

 (inches) 



19.60 

 20.50 

 27.00 

 34.00 

 25.00 

 17.00 

 31.00 

 21.30 

 28.50 

 24.00 

 23.50 

 43.00 

 19.00 

 30.40 

 39.50 

 27.00 

 30.00 

 34.50 

 24.00 

 30.00 

 38.00 

 27.00 

 24.00 

 58.00 

 31.00 

 64.00 



Aspect 

 ratio 



2.40 

 1.90 

 2.80 

 4.60 

 3.30 

 2.33 

 2.25 

 2.70 

 2.80 

 3.00 

 3.60 

 5.23 

 2.17 

 2.43 

 3.25 

 2.62 

 4.30 

 2.95 

 2.67 

 4.20 

 4.10 

 2.25 

 1.70 

 3.00 

 2.46 

 2.72 



Wing- 

 tip slot 

 (actor 



1.42 

 .39 



.22 

 1.70 

 1.30 



.53 



.86 

 1.10 

 .08 

 .39 

 .13 

 1.20 

 1.60 

 .11 



1.30 

 2.80 

 .33 

 2.00 

 1.40 



Wrist- 

 slot fac- 

 tor 



.19 

 .17 

 .14 

 .11 

 .19 

 .22 

 .18 

 .26 

 .19 

 .13 

 .16 

 .12 

 .30 

 .20 

 .13 

 .20 

 .17 

 .15 

 .22 

 .15 

 .12 

 .27 

 .27 

 .12 

 .24 

 .14 



Number 

 of wing- 

 tip slots 



Column 1. — Gives the approximate weight in ounces. 



Column 2. — The wing loading is given in pounds of weight carried per square foot or 

 wing area. The area is taken to be the greatest projection of the 2 wings spread with 

 their tips at right angles to the body. 



Column 3. — Gives the weight in ounces carried per foot span of the wings. These units 

 wore chosen as giving figures of convenient size for drawing graphs. The span is taken 

 to be the distance between the wing tips when spread as for measuring area. 



Column 5. — The aspect ratio (or ratio of fineness) is arrived at by dividing the distance 

 between wing tip and body by the mean breadth. The mean breadth is obtained by taking 

 7 measurements along the direction of flight, at points situated %, ?i, etc., of the 

 length of the wing measured inwards from the tip. 



Column 6. — Gives the total length of slot that opens between separating feathers in 1 

 wing, as a fraction of the length of the wing measured from tip to body. The length of 

 any 1 slot has been taken to be the length of the shorter margin of the slot when it Is 

 fully open. 



Column 7. — Gives the length of the bastard wing as a fraction of the length of the 

 wing. As it is difHcult to determine how much of this winglet is actually operative, 

 owing to some of it being blanked off by small feathers near the root, the measurement 

 has, in all cases, been taken by sliding a ruler under it and pressing in toward the wing 

 root as far as possible. 



The figures given above are only 'n tended to give a rough idea of how the data vary 

 with different types of birds and different methods of fiying. They should not be con- 

 sidered as accurate, because they do not represent averages taken from a large number 

 of birds, and because accuracy in measurement of these things is well-nigh impossible. 



