Go to National Library of New Zealand Te Puna Mātauranga o Aotearoa
Volume 72, 1942-43
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Parasites.

No special efforts were made to collect ectoparasites from the owls, but a few specimens of fleas and lice were collected. I am indebted to Miss Clay, of the Department of Entomology of the British Museum of Natural History for identifying the louse, which was Philopterus cursitans (Nitzsch 1861), a species found on A. noctua in Europe also. Dr Karl Jordan, of the Zoological Museum, Tring, kindly identified the flea, Ceratophyllus gallinae (Schrank 1803).

The intestine and caeca of 24 birds were opened and their contents examined for endoparasites. The only one found was an extremely slender nematode worm, kindly identified for me by Dr Bayliss, of the British Museum, as Capillaria tenuissima (Rudolphi, 1803). Of these 24 birds, 9 had no parasites, 9 had them in the caeca only, 5 had them in the intestine only, and 1 had them in both, a solitary one in the intestine and many in the caeca. The caeca of owls are large and are peculiar in having the closed end expanded into a pear-shaped sac. They usually have dark coloured glutinous contents,

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unlike that of the intestine. The caeca only were examined in 20 owls, of which 6 contained nematodes. Infections were not very heavy. The 6 infected intestines contained only 15 worms, while 15 pairs of infected caeca contained 135 worms. This nematode is normally found in A. noctua in Europe. Two specimens of the Morepork, Ninox novaeseelandiae were also examined.*

It is interesting to find that while the introduced bird has only its introduced parasites, the native owl contained a cestode and two species of nematodes, one a Capillaria sp.

Though the numbers are not large enough to be conclusive there is a suggestion that the nematode is more common in the bush districts of South Otago and Southland than in the more open and drier Central Otago and Canterbury. Five birds were received from the Cromwell district and seven from localities in Canterbury. The intestine and caeca of two and the caeca only of the rest were examined and none contained nematodes. As will be seen from the figures given above, among the 32 southern birds examined, one individual out of every three had the parasites in its caeca.

In Europe the owl is known to be the host of certain Haemosporidia. No special attempt was made to look for the presence of these, but the blood of one or two specimens was examined. No blood parasites were noticed.

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Table IV.
Mean Monthly Weights of the Owls.
Male. Female.
No. of Birds. Mean Weight. Lightest. Heaviest. No. of Birds. Mean Weight. Lightest. Heaviest.
June 1 219 1 200
July 3 230 203 253 2 233 227 238
August 3 200 198 201 2 201 175 227
September 2 176 166 186 6 174 141 189
October 6 165 143 187 4 192 174 231
November 4 156 142 180 2 209 189 229
December 9 157 148 175 6 161 139 177
January 2 166 142 191
February 6 175 139 203 13 170 163 181
March 7 185 141 216 2 147 143 151
April 7 173 142 192 8 180 148 210
May 6 172 146 191 9 201 173 220
June 4 213 212 215 9 230 142 298
July 2 215 206 225 3 193 167 210
August 2 217 208 227 1 176
September 1 170 4 178 164 211
October 1 203
November 1 146
December 2 148 145 152 2 155 149 161
January 1 146 1 173
February 1 148 1 167
March 6 159 148 178 5 157 147 169
April 17 169 148 193 17 175 154 206
May 1 158 1 184
June 1 273 2 228 223 234

[Footnote] * It should be noted that neither of these Moreporks met its death because of the investigation. One was found dead and the other was killed in mistake for a Little Owl on the ground that it destroyed native birds.

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Graph showing the monthly changes in mean body weight of the two sexes during the period June, 1938, to June, 1940.