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Summary Taylor, P. B. 1985. Field studies of the African Crake Crex egregia in Zambia and Kenya. Ostrich 56: 170–185. Field observations were made of a breeding population of African Crake Crex egregia at Ndola, Zambia from 1975 to 1980 and of a nonbreeding population at Mombasa, Kenya in 1981. Both populations are migratory and the Kenyan birds are thought to breed in southern Africa. Habitat requirements, migrations and patterns of occurrence are described. Population estimates give the density of breeding birds as 1 bird/2,6ha and of nonbreeding birds as 1 bird/1,99-2,73 ha. Local movements are evident at Mombasa. The crakes are thought to be territorial in both the breeding and nonbreeding seasons and the pair bond is sustained or formed during the nonbreeding season. Habits and behaviour are described, including courtship, copulation, aggression, feeding, roosting and vocalizations. Breeding, moult and predation are briefly discussed.

Most Corn crake territories were located in hayfields; these and marshes were the preferred nesting habitat. Since 1982 there has been a major reduction in Corncrake numbers on Canna. Although there have been minor habitat changes, the limited data on brood size and number suggest that much of the habitat on the island is still suitable for Corncrakes. Information from retrapping calling adults showed a very low return rate, as has been found in Sweden. The recent decline may be due to higher mortality on migration, as conditions in the breeding area on Canna and the wintering areas do not appear to have changed significantly.

From the early 1990s through 2005, we conducted butterfly transect surveys annually at the same sites in three regions of Wisconsin. We compared specialist butterfly population indices at three sites where a permanent non-fire refugium (a unit kept unburned through cycles of rotational fire elsewhere in the site) was established during this study to indices at comparison sites (which had consistent management throughout this study) in the same region. At Crex Meadows (12,180 ha), all significant changes in specialist numbers skewed toward relatively higher abundance in the refugium (14 ha, last burned in 1988) during the later period (1998–2005) versus 10 comparison subsites (fire-managed in both periods) than expected from observations in the earlier period (1991–97). The same pattern occurred in the refugium (4 ha) at Bauer-Brockway (125 ha), after the rest of that unit (9 ha) had its first management fire. Population trends were positive in these refugia, while the comparison sites usually had less favorable trends, or otherwise had similar trends. At Muralt Bluff (25 ha), regal fritillaries (Speyeria idalia) were more concentrated in the refugium (3 ha, last burned in 1991) during the earlier period but were more abundant in both periods in the refugium than the other units there (fire-managed in both periods). In the earlier period at Muralt Bluff, this species significantly declined, the opposite trend of comparison sites (which always had never-burned refugia), but significantly increased in the later period, similar to comparison sites. The refugium did not benefit Ottoe skipper (Hesperia ottoe), which declined significantly in the earlier period and was not recorded in the later period. Formerly burned units began functioning as refugia only >6–8 years after last fire and continued to increase in benefit for years after that. In fire-managed and fire-prone sites, we recommend the creation of permanent non-fire refugia for Lepidoptera conservation, placed where the most specialists will benefit and managed unintensively (e.g. mowing) if needed.

Acoustically identifying individuals may be a helpful technique when it is necessary to monitor animal populations over space and time. Previous studies have largely focused on the theoretical exploitation of vocal individuality or have looked at a small number of individuals. Here, we examined whether vocal individuality can be used to track the movement of individuals within a population (in this case when the number of individuals is greater than 100) and unknown beforehand. As a model species, we used the Corncrake (Crex crex)—a highly secretive bird whose calls are characterized by an individual-specific feature: pulse-to-pulse duration (PPD). When we performed classical discriminant function analyses on PPD, we correctly identified a high percentage of individuals (>98 %), even when sample size was larger than 100. However, a comparison of PPD similarity within and between individuals showed that, while birds can be correctly discriminated, unambiguous identification is impossible when the number of individuals is unknown beforehand. Therefore, we were only able to assess the probability that two calls belonged to the same individual. The results of this study show that acoustic identification in the Corncrake, and probably in other animal species, is mainly useful in detecting general behavioral patterns within populations. For instance, we discovered that more than 50 % of males change territories during the breeding season, probably to find females. Physical marking methods seem to be more reliable to tracking specific individuals. However, those methods usually consider limited numbers of individuals. Therefore, generalizing results to the population scale can also be misleading.

Microgeographic variation in bird song has been studied in many species. However, it remains to be more fully described in birds that do not learn song and that thus have largely innate vocalisations. In this study, we focused on microgeographic variation in the territorial calls of one such non-learning species, the Corncrake (Crex crex). We examined the temporal and spectral characteristics of male Corncrake calls recorded in five separate populations in Poland. We found significant but weak relationships between some of the call characteristics and between-caller distances in four populations. The patterns observed were inconsistent. For some call characteristics, similarity decreased as distance between callers increased, while the opposite was true for other characteristics. Moreover, the same call characteristics showed opposite patterns in different populations or even within the same population but in different years. These findings suggest that the specific spatial distribution of the different quality habitats in which populations are located may have a crucial influence on microgeographic variation in calls. Alternatively, in non-learning species, various levels of microgeographic variation in calls might arise independently as a consequence of (1) social interactions among males, during which birds modify some parameters of their inherited call; or (2) territory occupancy patterns that minimize or maximize call similarity among neighbours.

Crex Meadows, located in the sand barrens of northwestern Wisconsin, has a vegetational composition of wetlands mixed with jack pine-scrub oak prairie savanna. The vegetational history of this prairie-forest ecotone starts with the examination of the written records and journals of early explorers, and continues through the effects of pre-European settlement, major European settlement, and present-day changes. The pre-settlement vegetation of Crex is examined and compared quantitatively to presentday vegetation using the original surveyors' records. Past vegetation of natural prairie was maintained by fire and the current prescribed burning performed by the Wisconsin Conservation Department has restored the area to a state similar to that of pre-settlement times, brush prairie savanna.