The influence of predation risk on foraging behaviour of brushtail possums in Australian woodlands

The potential effects of predation risk on common brushtail possums were investigated in south-eastern Australian woodlands. Patterns of habitat use, foraging costs using giving-up density (GUD) experiments, and indices of body condition and reproductive success were examined at eight sites in two habitat types (eucalypt- or cypress-pine–dominated stands), within three areas of different red fox abundance (high, moderate and low fox density). In cypress-pine–dominated stands, possums travelled further on the ground, visited more feeding stations and had lower GUDs at feeders where foxes were removed than did possums in high-fox-density sites. In contrast, there was no effect of fox removal on the behaviour of possums in eucalypt-dominated stands. Fox removal also had no effect on indices of body condition and reproduction. Minor effects of microhabitat were detected with trackplot and GUD experiments, but, overall, the results suggest that habitat at the stand-level was more important. The non-lethal effects of foxes in different habitats may need to be taken into account when developing conservation strategies for native marsupials.

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Glucocorticoids, state-dependent reproductive investment and success in the face of danger in a long-lived bird

Journal of Ornithology ◽

10.1007/s10336-020-01847-9 ◽

2020 ◽

Author(s):

Kristina Noreikienė ◽

Kim Jaatinen ◽

Benjamin B. Steele ◽

Markus Öst

Keyword(s):

Predation Risk ◽

Telomere Length ◽

Clutch Size ◽

Body Condition ◽

Nest Predation ◽

Hatching Success ◽

Reproductive Investment ◽

Trade Off ◽

Relative Telomere Length ◽

Future Reproduction

AbstractGlucocorticoid hormones may mediate trade-offs between current and future reproduction. However, understanding their role is complicated by predation risk, which simultaneously affects the value of the current reproductive investment and elevates glucocorticoid levels. Here, we shed light on these issues in long-lived female Eiders (Somateria mollissima) by investigating how current reproductive investment (clutch size) and hatching success relate to faecal glucocorticoid metabolite [fGCM] level and residual reproductive value (minimum years of breeding experience, body condition, relative telomere length) under spatially variable predation risk. Our results showed a positive relationship between colony-specific predation risk and mean colony-specific fGCM levels. Clutch size and female fGCM were negatively correlated only under high nest predation and in females in good body condition, previously shown to have a longer life expectancy. We also found that younger females with longer telomeres had smaller clutches. The drop in hatching success with increasing fGCM levels was least pronounced under high nest predation risk, suggesting that elevated fGCM levels may allow females to ensure some reproductive success under such conditions. Hatching success was positively associated with female body condition, with relative telomere length, particularly in younger females, and with female minimum age, particularly under low predation risk, showing the utility of these metrics as indicators of individual quality. In line with a trade-off between current and future reproduction, our results show that high potential for future breeding prospects and increased predation risk shift the balance toward investment in future reproduction, with glucocorticoids playing a role in the resolution of this trade-off.

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Design of experimental food patches to measure foraging intensity for octopus: a case study with the giant Pacific octopus Enteroctopus dofleini

Journal of Molluscan Studies ◽

10.1093/mollus/eyaa039 ◽

2020 ◽

Author(s):

Stephanie Chancellor ◽

David Scheel ◽

Joel S Brown

Keyword(s):

Predation Risk ◽

Foraging Behaviour ◽

Habitat Preferences ◽

High Tide ◽

Intertidal Habitat ◽

Camera System ◽

Subtidal Habitat ◽

Enteroctopus Dofleini ◽

Nontarget Species

ABSTRACT In a study of the foraging behaviour of the giant Pacific octopus Enteroctopus dofleini, we designed two types of experimental food patches to measure habitat preferences and perceptions of predation risk. The first patch successfully measured giving-up densities (GUDs), confirmed by octopus prey presence and higher foraging at sites with historically greater octopus presence. However, nontarget foragers also foraged on these experimental food patches. Our second floating patch design successfully excluded nontarget species from subtidal patches, and from intertidal patches at high tide, but allowed for foraging by E. dofleini. The second design successfully measured GUDs and suggested that octopus preferred foraging in a subtidal habitat compared to an intertidal habitat. We ascribe the higher GUD in the intertidal habitat to its higher predation risk relative to the subtidal habitat. The second patch design seems well suited for E. dofleini and, in conjunction with a camera system, could be used to provide behavioural indicators of the octopus's abundance, perceptions of habitat quality and predation risk.

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Relation of Automated Body Condition Scoring System and Inline Biomarkers (Milk Yield, β-Hydroxybutyrate, Lactate Dehydrogenase and Progesterone in Milk) with Cow’s Pregnancy Success

Sensors ◽

10.3390/s21041414 ◽

2021 ◽

Vol 21 (4) ◽

pp. 1414

Author(s):

Ramūnas Antanaitis ◽

Vida Juozaitienė ◽

Dovilė Malašauskienė ◽

Mindaugas Televičius ◽

Mingaudas Urbutis ◽

...

Keyword(s):

Lactate Dehydrogenase ◽

Reproductive Success ◽

Milk Yield ◽

Body Condition ◽

Body Condition Score ◽

The Body ◽

Time Analyzer ◽

Condition Score ◽

Pregnancy Status ◽

Body Condition Scoring

The aim of the current study was to evaluate the relation of automatically determined body condition score (BCS) and inline biomarkers such as β-hydroxybutyrate (BHB), milk yield (MY), lactate dehydrogenase (LDH), and progesterone (mP4) with the pregnancy success of cows. The cows (n = 281) had 2.1 ± 0.1. lactations on average, were 151.6 ± 0.06 days postpartum, and were once tested with “Easy scan” ultrasound (IMV imaging, Scotland) at 30–35 d post-insemination. According to their reproductive status, cows were grouped into two groups: non-pregnant (n = 194 or 69.0% of cows) and pregnant (n = 87 or 31.0% of cows). Data concerning their BCS, mP4, MY, BHB, and LDH were collected each day from the day of insemination for 7 days. The BCS was collected with body condition score camera (DeLaval Inc., Tumba, Sweden); mP4, MY, BHB, and LDH were collected with the fully automated real-time analyzer Herd Navigator™ (Lattec I/S, Hillerød, Denmark) in combination with a DeLaval milking robot (DeLaval Inc., Tumba, Sweden). Of all the biomarkers, three differences between groups were significant. The body condition score (BCS) of the pregnant cows was higher (+0.49 score), the milk yield (MY) was lower (−4.36 kg), and milk progesterone in pregnant cows was (+6.11 ng/mL) higher compared to the group of non-pregnant cows (p < 0.001). The pregnancy status of the cows was associated with their BCS assessment (p < 0.001). We estimated that cows with BCS > 3.2 were 22 times more likely to have reproductive success than cows with BCS ≤ 3.2.

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The influence of roost closure on the roosting and foraging behaviour of Eptesicus fuscus (Chiroptera: Vespertilionidae)

Canadian Journal of Zoology ◽

10.1139/z86-169 ◽

1986 ◽

Vol 64 (5) ◽

pp. 1128-1133 ◽

Cited By ~ 83

Author(s):

R. Mark Brigham ◽

M. Brock Fenton

Keyword(s):

Reproductive Success ◽

Direct Observation ◽

Foraging Behaviour ◽

Eptesicus Fuscus ◽

Maximum Distance ◽

Radio Tracking ◽

Site Specific ◽

Big Brown Bats ◽

Specific Factors ◽

Foraging Flight

We used radio tracking and direct observation to determine the effect of roost closure on the roosting and foraging behaviour of big brown bats (Eptesicus fuscus) in maternity colonies near Ottawa. Individuals were site loyal, but after eviction they moved short distances to new roosts where they tended to produce fewer offspring. The time spent on the first foraging flight, the maximum distance travelled, and the use of feeding areas did not change with exclusion. The results suggest that bats roost to take advantage of site-specific factors that may increase reproductive success.

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Foraging behaviour of the Peaceful Dove (Geopelia striata) in relation to predation risk: group size and predator cues in a natural environment

Emu - Austral Ornithology ◽

10.1071/mu12023 ◽

2013 ◽

Vol 113 (1) ◽

pp. 1-7 ◽

Cited By ~ 2

Author(s):

Lei (Stanley) Tang ◽

Lin Schwarzkopf

Keyword(s):

Predation Risk ◽

Group Size ◽

Natural Environment ◽

Foraging Behaviour ◽

Risk Group ◽

Predator Cues

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Effects of parental body condition and size on reproductive success in a tenebrionid beetle with biparental care

Ecological Entomology ◽

10.1111/j.0307-6946.2004.00618.x ◽

2004 ◽

Vol 29 (4) ◽

pp. 410-419 ◽

Cited By ~ 8

Author(s):

Dik Heg ◽

O. Anne E. Rasa

Keyword(s):

Reproductive Success ◽

Body Condition ◽

Biparental Care ◽

Tenebrionid Beetle

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Modification of 0+ perch foraging behaviour by indirect cues of predation risk

Ecology Of Freshwater Fish ◽

10.1111/j.1600-0633.2006.00139.x ◽

2006 ◽

Vol 15 (2) ◽

pp. 118-124 ◽

Cited By ~ 9

Author(s):

J. Wanzenbock ◽

V. N. Mikheev ◽

A. F. Pasternak

Keyword(s):

Predation Risk ◽

Foraging Behaviour ◽

Indirect Cues

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Assisted colonisation trial of the eastern barred bandicoot (Perameles gunnii) to a fox-free island

Wildlife Research ◽

10.1071/wr16198 ◽

2017 ◽

Vol 44 (7) ◽

pp. 484 ◽

Cited By ~ 6

Author(s):

Rebecca Groenewegen ◽

Dan Harley ◽

Richard Hill ◽

Graeme Coulson

Keyword(s):

Habitat Use ◽

Body Condition ◽

Red Fox ◽

Suitable Habitat ◽

Viable Option ◽

Predator Exclusion ◽

In The Wild ◽

Radio Transmitters ◽

Release Group ◽

Small Sites

Context Assisted colonisation has the potential to protect species from intractable threats within their historical ranges. The Australian mainland subspecies of the eastern barred bandicoot (Perameles gunnii) is extinct in the wild, with surviving populations restricted to small sites protected by predator–barrier fences. PVA modelling shows that a self-sustaining bandicoot population would require an area free of the introduced red fox (Vulpes vulpes) of at least 2500ha. French Island is outside the historic range of the species, but is fox-free and contains around 9000ha of potentially suitable habitat. Aims This study will assess the suitability of French Island as a potential site for a self-sustaining eastern barred bandicoot population by conducting a 1-year assisted colonisation trial to assess habitat use, body condition and survival. Methods Between July and September 2012, 18 adult bandicoots were released. We radio-tracked bandicoots using intraperitoneal radio-transmitters for up to 122 days and trapped fortnightly. Key results The release group met the three measures of success: (1) appropriate habitat use; (2) recovery of post-release bodyweight; and (3) founder survival exceeding 100 days. Habitat use and body condition throughout the trial reflected that of mainland populations, and seven bandicoots survived longer than 100 days. Mortality was greatest in the first month, with veterinary investigations confirming two deaths due to cat predation, two deaths from toxoplasmosis and one unknown cause of death. Bandicoots that survived longer than 100 days occupied higher, drier ground than those that did not. Toxoplasmosis cases were associated with lower topographic position on the site. Conclusions Our results suggest that French Island provides suitable habitat for the establishment of a population of eastern barred bandicoots. On French Island, toxoplasmosis was identified as an important source of mortality in addition to cat predation, and warrants further investigation. Implications Given the costs and challenges of predator control and the maintenance of predator exclusion fences, assisted colonisation to one or more fox-free islands remains the most viable option to establish self-sustaining bandicoot populations. Our results highlight the value in conducting trial releases ahead of major translocations.

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