Geology topics
Source-linked reports with geographic coverage including Patuxent Wildlife Research Center.
A free-flying Canada goose ( Branta canadensis interior ), known to be just under a year old, laid a clutch of four eggs at the Patuxent Wildlife Research Center. At least half of the 2-year-old females nest at Patuxent, and almost all of the 3-year-olds nest. As far as we know, this is the first record of nesting by a yearling Canada goose.
Examination of blood films from wood ducks ( Aix sponsa ) from several northeastern states revealed Haemoproteus , Leucocytozoon , Plasmodium and a typanosome. Haemoproteus occurred in all areas sampled and birds of the year from Massachusetts demonstrated the highest incidence during the last 2 weeks in August. Leucocytozoon was most prevalent in more northern areas. P. circumflexum and a trypanosome are reported for the first time from this host.
The finding of Cnephia ornithophilia Davies, Peterson, & Wood and Prosimulium vernale Shewell for the first time at the Patuxent Wildlife Research Center, Laurel, Maryland, is described. Larvae of C. ornithophilia were collected Nov. 15, pupae Feb. 14, and adult flies Feb. 28. No immature or adult specimens were found between Apr. 2 and Nov. 14. The greatest number of immature stages was found in a 3- to 5-foot-wide stream several hundred feet long, 1-8 inches deep, with a stream flow between 0.49 and 3.30 feet per second. The water temperature varied from 0.5° to 4.0°C, the oxygen content was 10-13 ppm; and the p H varied from 6.9 to 7.4. Larvae of P. vernale were collected Nov. 30 through March, pupae from February through Apr. 1, and adult flies from Feb. 26 through Apr. 1. No immature or adult specimens were found between Apr. 2 and Nov. 29. The largest number of immature stages of P. vernale was found in a 6- to 16-foot-wide stream, 100 feet long, and 1.2 inches deep. The stream flow was between 0.92 and 1.36 feet per second. The water temperature was 0.5°C; p H was 6.7; and oxygen content was 7 ppm.
A colony of kestrels ( Palco sparverius ) was established at the Patuxent Wildlife Research Center in 1964 in connection with work on pesticides. The kestrels were acquired from the wild, both as nestlings and as full-grown birds, and were housed in several rows of outdoor pens. Each 50 x 20 ft pen was covered with wire netting and had its long sides in common with adjacent pens. During the first two reproductive seasons, untreated parent birds (dosed birds are not included in this paper) ate eggs and young. Cannibalism virtually ceased after the diet was changed from ground beef or horsemeat supplemented with liver, vitamins, and minerals to one containing a finely ground mixture of laboratory rodents, chicken heads, skinned chicken necks, and supplements; hatching success thereafter generally equaled that of a wild population. In 1967, 16 pairs of untreated hawks (3-year-old females) laid clutches averaging 4.9 eggs, hatched 88 percent of their eggs, and fledged 88 percent of their young. In 1968, 10 pairs of this group (4-year-old females) laid clutches averaging 4.9 eggs, hatched 51 percent of their eggs, and fledged 85 percent of their young. Nine yearling pairs (hatched in captivity) laid clutches in 1968 averaging 5.1 eggs, hatched 87 percent of their eggs, and fledged all of their young.
The first known record of Hooded Mergansers ( Lophodytes cucullatus ) nesting on the coastal plain of Maryland was in 1961, when Mr. Francis Uhler (pers. comm) found two clutches in Wood Duck nest boxes in impoundments at the Patuxent Wildlife Research Center, about five miles southeast of Laurel, Maryland. R.E. Stewart and C.S. Robbins (“Birds of Maryland and the District of Columbia,” N. Amer. Fauna no. 62, 1958; see p. 102) reported two records of broods for Maryland, one for the Piedmont and one for the mountains.
Filarioid worms ( Dirofilaria immitis , D. tenuis , Dipetalonema procyonis , and D. llewellyni ) were discovered in raccoons ( Procyon lotar ) in Maryland. Raccoons were trapped in lowland, upland, and agricultural-residential areas, which were further classified as stream borders, poorly drained, and well drained. Data on incidence of D. llewellyni were analyzed on basis of host distribution within these areas to indicate type of habitat in which one might seek the vector. It was concluded that exposure takes place in the spring of the year. The arthropod found associated most often with the raccoon in spring was Ixodes texanus . Larvae of this tick which were fed on infected raccoons presented no evidence of development of the microfilariae. Feeding experiments were also conducted with mosquitoes: Aedes aegypti , A. canadensis , A. sollicitans , A. triseriatus , A. vexans , Culex pipiens , Anopheles punctipennis , and A. quadrimaculatus . Although microfilariae remained alive and active in the gut contents of all these mosquitoes for 2 days, only in Aedes aegypti did they enter the hemocele, but no developmental changes were noted and all microfilariae were dead by the eighth day. Although the intermediate host of D. llewellyni was not determined, evaluation of the accumulated data provides criteria for seeking the vector. It appeared unlikely that exposure of the raccoons took place in the den or that the filarioids were transmitted by an ectoparasite commonly found in raccoon dens. The data suggest that the vector is available only early in spring, although there are infected raccoons throughout the year. Prevalence in juveniles was 21 percent; in subadults, 64 percent; in adults, 87 percent.