Understanding sitatunga (Tragelaphus spekii) habitats through diet analysis in Rushebeya‐Kanyabaha wetland,Uganda

Between January and December 2008, we assessed the diet and habitat selection of sitatunga, a highly endangered tropical wetland antelope threatened by habitat loss in Rushebeya‐Kanyabaha wetland. Microhistological faecal analysis and vegetative sampling methods were used to assess plant forms, species and seasonal changes in the sitatunga diet. Habitat use was indirectly determined by assessing feeding patterns, distribution of dung and trails within the wetland. Sitatunga fed mainly on herbs, sedges, grasses and shrubs. A total of 34 plant species were recorded as eaten by sitatunga. The most eaten plant species was Cyperus papyrus L. (22%). Malenthera scandens Schum. & Thonn., Polygonum senegalense Meisu (12%) and Polygonum pulchrum Blume (5%) were the most eaten herbs. Zea mays L. was the most eaten agricultural crop (58% of domestic crops), mainly during the wet season. Sitatunga feeding was mainly concentrated on the wetland edge habitat (46%) where most of its food (53%) was located. The other preferred habitat was the tall closed papyrus. We conclude that the long‐term survival of sitatunga requires a management plan focussing on the conservation of the most preferred plant species and habitats.     

SOME OBSERVATIONS ON THE SITATUNGA IN KENYA

A 16-month study was made of sitatunga in a swamp in western Kenya, with particular reference to distribution within the habitat, daily activity, and food preferences. Absolute figures for density could not be obtained because of observational difficulties, but there was a minimum of 7.3 animals/linear km of swamp, or c. 55/km². The sitatunga preferred areas of swamp adjacent to patches of gallery forest, and areas where there was deep water and a dense growth of tall reeds. They were most active during the first five and last two hours of daylight, and at night. Much of this time was spent feeding. Feeding behaviour and food preferences were studied. The sitatunga usually moved along well-marked tracks through the swamp vegetation; some of these led to beds of flattened plants, raised above water level, which were probably used for resting and for breeding. The latter took place in most months of the year, with a possible peak in November. Calves remained hidden for some weeks after birth. Group size and structure were examined; most sightings were of single animals or groups of two. A majority of these two groupings were composed of adult females. The proportion of immature animals seen indicated a healthy population. Courtship behaviour was observed 18 times and mating once.     

Chromosome studies of a fertile mammalian hybrid: the offspring of the cross bongo × sitatunga (Bovoidea)

The offspring of the cross bongo (Boocercus euryceros), 2n = 33 x sitatunga (Tragelaphus spekei), 2n = 30, has proved to be fertile. This fertility shows that the relationship between the karyotypes of the parental species is a simple one, despite the different diploid numbers and a different sex chromosome determinism, XX/XY in the sitatunga, XX/Y-to-autosome translocation in the bongo:meiotic processes and gametogenesis are not impaired in the hybrid.     

Feeding patterns of sitatunga (Tragelaphus Speki) in the Rushebeya‐Kanyabaha wetland,south western Uganda

Feeding patterns and habits of sitatunga were assessed in Rushebeya‐Kanyabaha wetland between June 2006 and July 2007. Sixty transects were cut at intervals of 250 m along which sitatunga dung piles, habitats used and diet were identified from feeding signs or plant damage. Household interviews were also conducted in villages adjacent to the wetland to understand plants and crops known to be fed on by sitatunga, type of damage, frequency of sitatunga farm visits and their methods to control crop raiding. Sitatunga mostly fed on leaves (60%) and in the wetland edge (WE) habitat (49%). Forty plant species were recorded to be eaten with herbs as majority (33%) and of crops sweet potatoes were most raided. Sitatungas are basically solitary species with 73% of the sightings being of a single individual. They had mornings and late evenings as their movement peaks and preferred to feed on broad leaved plants. There were significant relationships between both habitat use and food preferences with seasons. We predict that because of seasonal food variations, crop raiding would increase and may result into more negative attitudes by farmers to sitatunga. More research on farmers’ sensitization, population census, behaviours and ecotourism are necessary for this species conservation.     

Temperature effects on “overwintering” phenology of a polyphagous,tropical fruit fly (Tephritidae) at the subtropical/temperate interface

Around the world, several pest tephritids are extending their ranges from warm tropical or Mediterranean climates into cooler temperate regions. The ability to tolerate climatic diversity is uncommon among insects, and understanding the population phenology drivers of such species across different parts of their range will be critical for their management. Here, we determined the role of temperature versus fruit availability on the population phenology of Queensland fruit fly, Bactrocera tryoni. Using a field site located at the subtropical/temperate interface, with host fruits continuously available, we monitored the development times and abundance of B. tryoni, a species which has invaded temperate Australia from the tropics. From fruit samples held at ambient and controlled conditions, the abundance of emerging flies was highly variable among collection dates, but the variance did not reflect the observed changes in temperature. For most samples, the survival rate of flies in a field site was lower than predicted by a day‐degree population model fitted with mean daily field temperatures. The development time of the immature stage in the field was prolonged, presumably due to cooler ambient conditions, but the fitted day‐degree population model consistently over‐predicted estimated development times. Our results indicate that at the subtropical/temperate interface, the decline in B. tryoni populations during winter is only partly driven by temperature and host availability. We classify B. tryoni as a climate generalist, which likely employs physiological as well as behavioural mechanisms to achieve broad climatic tolerance ranges.     

Comparison of Day and Night Fyke Netting, Electrofishing and Snorkelling for Monitoring a Population of the Threatened Golden Galaxias (Galaxias auratus)

The littoral zone of small off-stream water storage containing a translocated population of Galaxias auratus was sampled fortnightly at day and night with fyke nets, electrofishing and snorkelling over 3 months. Variation in population data provided by each method, including relative abundance indices, size structure, and habitat preferences, were examined. Aspects of behaviour and activity patterns were also investigated. Night sampling using all methods consistently yielded larger catches than day sampling. The size structure of catches varied, with electrofishing at night and fyke netting during the day having higher proportions of juveniles, whilst snorkelling at night and electrofishing during the day had higher proportions of adults. Fyke netting at night yielded by far the largest catches (~3-fold more than other methods) and also captured balanced proportions of juveniles and adults. Galaxias auratus had a strong diel activity pattern and were most active at night. The majority of the population migrated into the littoral zone during the night and back into deeper water during the day. A small number of juveniles remained in the littoral zone and some adults sheltered in the dense cover of species-rich littoral vegetation during the day. Shores with shallow depth profiles appeared to be preferred due to higher catches in these areas using all methods. Based on the results of this study, fyke netting at night in littoral habitats is recommended for monitoring populations of G. auratus. Fyke netting is likely to be an effective method for monitoring other lacustrine galaxiid species; however, further work is required to investigate the effects of habitat variables and fish community structure on activity patterns of galaxiids, and hence their catchability with various methods, in more extensive lentic environments.     

Foraging strategies of Eriophora transmarina and Nephila plumipes (Araneae: Araneoidea): Nocturnal and diurnal orb-weaving spiders

Abstract The foraging behaviour, web characteristics and prey availability of two sympatric orb-weaving spiders, Nephila plumipes and Eriophora transmarina (Araneae: Araneoidea), are compared. The spiders are similarly sized but have different temporal foraging patterns. Nephila plumipes spins a relatively permanent web and captures most of its prey during the day. Eriophora transmarina only forages at night, spinning a new web every night and usually dismantling it at dawn. These different foraging activities are most likely to be responsible for the observed differences in the types and rates of prey capture: E. transmarina captured mostly Lepidoptera that were more abundant at night than during the day, while N. plumipes captured mostly Hymenoptera that were more abundant during the day than at night. While nocturnal E. transmarina have less time available for foraging than the diurnal N. plumipes, the former has a substantially higher nocturnal prey capture rate. We argue that the difference between the species in their prey capture rates are likely to be due to differences in the architecture of their webs.     

Are subordinate ants the best seed dispersers? Linking dominance hierarchies and seed dispersal ability in myrmecochory interactions

True myrmecochory involves the dispersal of elaiosome-bearing seeds by ants. Between the guild of ants that are attracted to these seeds, only a few of them will act as effective dispersers, that is, transporting the seeds to suitable sites (the nests) for germination and plant establishment. Ant communities are known to be highly hierarchical, and subordinate ants quickly deliver resources to their nest rather than consuming it on-site, thereby avoiding encounters with more dominant species. As a result of a series of studies that were carried out during summer in semi-arid Northwest Argentina, we have found that the most important seed disperser of the myrmecochorous plant Jatropha excisa Griseb. (Euphorbiaceae), the ant Pogonomyrmex cunicularius pencosensis Forel, was the most subordinate species during interspecific interactions. The daily timing of release of the J. excisa seeds through ballistic dispersal increased their probability of being removed by the highly thermophilic P. cunicularius pencosensis. Foraging during the warmest hours of the day allowed P. cunicularius pencosensis ants to avoid the risk of interference competition with dominant species, which also behaved as elaiosome predators. As a conclusion, subordinance behaviour appears to be integral to successful myrmecochory, and also the timing of seed release plays a key role in shaping the dynamics of myrmecochorous interactions. Therefore, ant-dispersed plants should not only favour their discovery by subordinate ants, but also should present their seeds at those times of the day when the behaviourally dominant ants are less active.     

Spring development of a Chlamydomonas population in Lake Nimetön,a small humic forest lake in southern Finland

Biomass development and vertical distribution of a Chlamydomonas population in a small humic forest lake was followed by daily sampling in May-June, 1984. Chlamydomonas dominated the phytoplankton spring bloom, forming 71% of the maximum phytoplankton biomass on 18 May. In early May the outflow rate was high and during the 24 hour period when the maximum rate of surface runoff was recorded (8–9 May), 43% of the Chlamydomonas biomass was flushed out of the lake, which delayed the onset of biomass increase. When surface runoff had slowed down Chlamydomonas biomass started increasing and during wax of the population most cells were < 10 µm in diameter. Population maximum lasted for one day (18 May) and there-after Chlamydomonas biomass decreased towards the end of the study. During wane of the population most cells were > 10 µm in diameter.     

Age,seasonal and diel variations of the uricolytic enzymatic system in the snailsXeropicta arenosa (Ziegler) andCernuella virgata (Da Costa)

Summary The nitrogen catabolism of two snail species,Xeropicta arenosa andCermuella virgata, living on coastal dunes, was studied at different seasons and times of the day and at different ages. All the nitrogenous metabolites of the uricolytic enzymatic system were found in body homogenates of the snails, although uric acid was most abundant. The highest levels of these catabolites were observed during the day when the snails were inactive, while the lowest levels occurred during the night when excretion probably took place. The levels of most of the nitrogenous catabolites and the activities of the enzymes were higher in juveniles than in adults.All the enzymes of the uricolytic pathway were shown to be present in bothX. arenosa andC. virgata.     

Wait Until Dark? Daily Activity Patterns and Nest Predation by Snakes

Predation involves costs and benefits, so predators should employ tactics that reduce their risk of injury or death and that increase their success at capturing prey. One potential way that predators could decrease risk and increase benefits is by attacking prey at night when risks may be reduced and prey more vulnerable. Because some snakes are facultatively nocturnal and prey on bird nests during the day and night, they are ideal for assessing the costs and benefits of diurnal vs. nocturnal predation. We used automated radiotelemetry and cameras to investigate predation on nesting birds by two species of snakes, one diurnal and the other facultatively nocturnal. We predicted that snakes preying on nests at night should experience less parental nest defence and capture more adults and nestlings. Rat snakes (Pantherophis obsoletus) were relatively inactive at night (23–36% activity) but nearly always preyed on nests after dark (80% of nest predations). Conversely, racers (Coluber constrictor) were exclusively diurnal and preyed on nests during the times of day they were most active. These results are consistent with rat snakes strategically using their capacity for facultative nocturnal activity to prey on nests at night. The likely benefit is reduced nest defence because birds defended their nests less vigourously at night. Consistent with nocturnal predation being safer, rat snake predation events lasted three times longer at night than during the day (26 vs. 8 min). Nocturnal nest predation did not make nests more profitable by increasing the likelihood of capturing adults or removing premature fledging of nestlings. The disconnect between rat snake activity and timing of nest predation seems most consistent with rat snakes locating prey during the day using visual cues but waiting until dark to prey on nests when predation is safer, although designing a direct test of this hypothesis will be challenging.     

Diurnal Variation in Feeding and Assimilation Rates of Planktonic Rotifers and its Possible Ecological Significance

Though rotifers play an important role in many pelagic ecosystems, there is a lack for studies on diurnal variations in feeding behaviour. Diurnal feeding rhythms of estuarine populations of Brachionus plicatilis and Keratella cruciformis f. eichwaldi and a pond population of K. cochlearis were investigated using ¹⁴C-Chlorella and ¹⁴C-labelled natural bacteria populations, respectively, as a tracer food during in situ experiments. A ⁵¹Cr/¹⁴C double tracer technique was used to determine Assimilation efficiencies. All species had about two times higher feeding rates during day than during dark hours. There was a tendency for higher values during the afternoon. No trend was found regarding diurnal changes in assimilation efficiency. Diurnally segregated niches between microphagous daytime active rotifers and nighttime active crustacean populations in pelagic ecosystems are demonstrated and their ecological significance with special regard to changes in food quality and predation pressure is discussed.     

Competition between hummingbirds and bumble bees for nectar in flowers of Impatiens biflora

Summary Using removal experiments and concurrent measurement of resource levels, evidence was obtained for exploitation competition between Ruby-throated hummingbirds and two bumble bee species (Bombus fervidus and B. vagans) foraging for nectar on Impatiens biflora.When all three species were active, flower visitors showed a complex pattern of resource partitioning involving both diel and spatial changes. Hummingbirds foraged almost exclusively from the outermost exposed flowers on plants from which they drained nectar levels beyond the reach of bees over most of the day. In contrast the longtongued bee species (B. fervidus), and the shorter-tongued B. vagans, displayed a preference for the innermost flowers on plants which were protected from hummingbird visitation by surrounding vegetation. The two Bombus spp. began foraging at different times during the day: B. vagans were most active in early morning but were replaced by B. fervidus later in the day.When hummingbirds were rare, only B. fervidus showed evidence of competitive release: an increase in the number of foragers and a broadening of flower choice to include more outer flowers. Workers of B. vagans showed a similar response to temporary removal of B. fervidus and also extended their foraging over the entire day. These responses were consistent with changes in the availability of nectar to different species.Removal experiments demonstrated that individuals of one species can be largely excluded from access to nectar resources as a direct result of exploitation of nectar by foragers of other species with longer tongues. Thus in this system interspecific exploitation is an important mechanism involved in resource partitioning.     

Observations on the behavior of captive sitatunga (Tragelaphus spekei)

Little is known about the behavior of the sitatunga. In order to learn more about their behavior, a group of sitatunga was studied at the Audubon Park and Zoological Garden. Courtship in the sitatunga begins with a male pursuing the female. The female occasionally stops, allowing the male to approach in the “low stretch” posture. If the female does not move away the male rests his chin on the female's rump and then mounts her. Males commonly horn branches, sticks, and turf. The possible functions of horning are discussed. Males also engage in sparring or “play-fighting.” Mutual grooming, vocalizations, and mother-young interactions of the sitatunga are described. The behavior of sitatunga is compared to that of other Tragelaphines.     

Diel interactions between prey behaviour and feeding in an invasive fish, the round goby, in a North American river

1. We studied the diet of the invasive round goby (Neogobius melanostomus) on a diel basis in the Flint River, a warmwater stream in Michigan, U.S.A. Diet and available prey samples were collected seven times over a 24 h period in four consecutive months. The section of river studied lacked zebra mussels (Dreissena polymorpha), the primary prey of adult round gobies elsewhere in the Great Lakes region. 2. Diet changed on a diel basis with hydropsychid caddisfly and chironomid larvae predominating during the day, chironomid pupae dominating in the evening and heptageniid mayflies dominating at night. Simultaneous study of macroinvertebrate drift suggested that caddisfly and chironomid larvae were most likely picked from submerged rocks, chironomid pupae were most likely taken during their emergent ascent and mayflies were either captured from the drift or picked from rocks. 3. The Flint River lacks a diverse darter (Family: Percidae) and sculpin (Family: Cottidae) fauna and it appears that the round goby has occupied a generalised darter/sculpin niche. Our results indicate that round gobies have the potential to invade successfully riverine systems, particularly those lacking a diverse benthic fish assemblage.     

HYBRID BREAKDOWN IN DEVELOPMENTAL TIME IN THE COPEPOD TIGRIOPUS CALIFORNICUS

Laboratory crosses were carried out among three genetically differentiated Los Angeles populations (all located within approximately 15 km) and one San Diego population (approximately 150 km away) of the intertidal copepod Tigriopus californicus. Despite high levels of allozyme differentiation, all crosses produced viable F₁ progeny. Most F₁ progeny had shorter developmental times and reduced variance in developmental times compared to the parental populations. Only one pair of populations failed to produce viable F₂ progeny; when the central Los Angeles population (AB) was crossed to the San Diego (SD) population, most larvae died during the late naupliar stages. Developmental times in the F₂ generation of the other Los Angeles × San Diego crosses were typically 40% longer than developmental times of the parental populations. Among the Los Angeles populations, only one cross (and not its reciprocal) showed a similarly large increase in developmental time. Variance in F₂ developmental times was greater than the parental variance in 5 of 10 crosses. These results are discussed with regard to the evolution of coadapted gene complexes and population differentiation in T. californicus.     

Temporal variation in feeding behaviour and trophic ecology of the temperate hemiramphid, <Emphasis Type="BoldItalic">Hyporhamphus melanochir</Emphasis>

The feeding ecology of southern garfish, Hyporhamphus melanochir, in South Australia was investigated to determine the dietary composition and diurnal feeding patterns, especially in relation to a hypothesised relationship between prey availability and feeding patterns. Samples of H. melanochir were collected at different times of the day and night during autumn and winter, and assigned to 3-hourly intervals. The dietary composition and feeding patterns were determined from gut contents analysis. The main food items were seagrasses (Zosteraceae) and hyperbenthic crustaceans, mainly amphipods. Polychaetes and insects were also consumed. A clear diurnal trophic shift was evident: seagrass was consumed in large volumes during the day, whilst hyperbenthic invertebrates dominated the diet during the night. Plankton samples indicated that this trophic shift reflected the higher abundances of hyperbenthic invertebrates in the water column at night. Less time was spent consuming seagrass during winter, coinciding with shorter day-lengths. H. melanochir has a strong trophic association with seagrass beds, which may account for the high garfish abundance in northern Gulf St. Vincent where extensive Zosteracean seagrass beds occur. This may be useful fundamental information for future environmentally-based fishery management decisions to help ensure the sustainability of southern garfish population and the ecosystem of which it is a part.     

Feeding selectivity of a tropical Chaoborus population

SUMMARY. The Chaoborus population of Lake Lanao, Philippines, was sampled weekly over a 65-week period. Specimens representing all four instars, all times of the year, and two points in the daily migration cycle were dissected for determination of gut contents. Major items in the diet of Lanao Chaoborus include Bosmina, Diaphanosoma, and the copepodid and adult stages of cyclopoid and calanoid copepods. Items that are available but seldom eaten include nauplii and rotifiers except Keratella. Feeding rate averages 2.5% of body weight per day in instars 3–4. Predator size affects but does not fully explain prey selection. Electivity values are much higher for Bosmina and Diaphanosoma than for copepods, even though these food items overlap in size. Bosmina, which has the highest electivity value of any prey, is virtually identical in size to the calanoid nauplius, which has one of the lowest electivity values. This and other similar data suggest that prey of the same size differ greatly in palatability or vulnerability. There is a marked variation in feeding rate and food composition from day to night. The smallest Chaoborus feed more during the day than at night, but the opposite is true for Chaoborus of moderate to large size. Large Chaoborus switch from a daytime emphasis on copepod copepodids and adults to a nighttime emphasis on Cladocera. Diurnal variation between instars in food composition cannot be explained simply on the basis of the vertical distributions of predators and prey. An interaction of vertical distribution with prey density and predator selectivity does explain the overall Chaoborus feeding pattern, however. During the day, larger Chaoborus move deep into the water column where food is scarce. Their daytime feeding rate is lower due to low prey density at great depths. Low prey density is partially compensated by relaxation of preference. At night, upward migration of large Chaoborus into an area of high prey density permits a resumption of marked selectivity and high feeding rates. Small Chaoborus do not descend deep into the water column during the day, as their lower hunting efficiency apparently requires higher food density and use of visual cues to sustain adequate feeding rates. Prey density thus affects both the vertical distribution and feeding selectivity of the Chaoborus population.     

The ecology and production of copepods, particularly Thermocyclops hyalinus, in the tropical Lake George, Uganda

(1) Total copepod numbers per litre in Lake George, Uganda, vary slightly during the course of a year. Numbers increase during the dry seasons June-August and January-February, and decrease during the rains. This variation is more marked in the mid-lake area, where copepod numbers are higher, but the change in numbers is not more than two-fold. By comparison with populations in temperate regions the population in Lake George is stable in size and shows little seasonal variation. (2) The carnivorous cyclopoid Mesocyclops leuckarti forms only 4–21 %, by num-bers, of the total copepod population and does not occur in numbers large enough to be analysed profitably. (3) The bulk of the population is the much smaller Thermoeyclops hyalinus and analysis of this population into the main development stages of its life history shows an almost constant age structure over the lake as a whole, throughout the year. (4) The development time of the eggs, as determined previously (Burgis, 1970), is 1–5 days. This, plus mean development-times of 6 and 11 days for nauplii and copepodites respectively, has been used to determine the daily rate of recruitment from each stage of the life history to the next. The recruitment from nauplii to copepodites and from copepodites to adults are very similar and almost constant. Recruitment from eggs to nauplii is. however, mueh greater, and it thus appears that the major loss to the population is at this eariy stage in the life history. This may well be due to predation by the larvae of Chaohorus. (5) Using this recruitment rate from eggs to nauplii, the potential turnover time of population numbers was calculated to have a mean value of 4–2 days for the lake as a whole. This is similar to maximum summer turnover times found by authors such as Hall (1964) for Daphnia populations in temperate waters. (6) The biomass of individuals at various stages in their life history was deter-mined as carbon, and application of these determinations to the numerical counts was used to calculate the standing-crop biomass in the lake. With a constant population of stable age-structure it is possible to estimate the daily biomass production from the turnover time of numbers. For the population of Thermocyelops hyalinus in Lake George this gives a mean figure of 211 μg C/I/day during 1969–70. (7) Instantaneous birth rates and instantaneous rates of change in population numbers (b and r) have also been calculated for the population of Thermocyclops. The values of r show some variation at one centre site, fluctuating around zero, but when calculated for lake mean figures r is hardly different from zero throughout the year. The values of b also show fluctuations when calculated for one site but when calculated for lake mean figures show no more than two-fold variations, being higher at the beginning of the two rainy seasons. The values of b are not as high as those attained during the summer in some temperate Daplmia populations such as those described by Wright (1965). The values of ZJ tend to be higher inshore than in mid-lake areas of the lake. (8) The instantaneous mortality rate r/has been calculated from b-r. With such very small values of r, d is always very similar to b. Most, if not all, recruitment to the population is counterbalanced by loss, probably predation. (9) At one inshore site the population was analysed and counted in detailed cate-gories, over a period of 10 days. This allowed a more accurate estimation of the standing-crop biomass and thus of production. A mean value of 103 μg C/l/day was obtained for these samples. (10) The mean daily level of production, c. 211 μg C/l/day, o(Thermocyclops hyalinus in Lake George, is among the higher values of zooplankton production available for comparison most of which are from temperate regions of the world. The fact that it is applicable throughout the year gives an annual value of 77g C/m³/year which is probably high.     

When and where to count? Implications of migratory connectivity and nonbreeding distribution to population censuses in a migratory bird population

Migratory connectivity is a metric of the co-occurrence of migratory animals originating from different breeding sites, and like their spatial dispersion, can vary substantially during the annual cycle. Together, both these properties affect the optimal times and sites of population censusing. We tracked taiga bean geese (Anser fabalis fabalis) during 2014–2021 to study their migratory connectivity and nonbreeding movements and determine optimal periods to assess the size of their main flyway population. We also compared available census data with tracking data, to examine how well two existing censuses covered the population. Daily Mantel's correlation between breeding and nonbreeding sites lay between 0 and 0.5 during most of the nonbreeding season, implying birds from different breeding areas were not strongly separated at other times in the annual cycle. However, the connectivity was higher among birds from the westernmost breeding areas compared to the birds breeding elsewhere. Daily Minimum Convex Polygons showed tracked birds were highly aggregated at census times, confirming their utility. The number of tracked birds absent at count sites during the censuses however exceeded numbers double-counted at several sites, indicating that censuses might have underestimated the true population size. Our results show that connectivity can vary in different times during the nonbreeding period, and should be studied throughout the annual cycle. Our results also confirm previous studies, which have found that estimates using marked individuals usually produce higher population size estimates than total counts. This should be considered when using total counts to assess population sizes in the future.