Preen Oil Research Articles

16S rRNA gene sequencing of microbiota from the preen oil and cloaca of chipping sparrows (Spizella passerina).

We present the results of 16S rRNA gene amplicon sequencing of the microbiota from preen oil and the cloaca of chipping sparrows (Spizella passerina) collected near Mountain Lake Biological Station in Pembroke, VA.

Microbial DNA extraction method for avian feces and preen oil from diverse species.

As DNA sequencing technology continues to rapidly improve, studies investigating the microbial communities of host organisms (i.e., microbiota) are becoming not only more popular but also more financially accessible. Across many taxa, microbiomes can have important impacts on organismal health and fitness. To evaluate the microbial community composition of a particular microbiome, microbial DNA must be successfully extracted. Fecal samples are often easy to collect and are a good source of gut microbial DNA. Additionally, interest in the avian preen gland microbiome is rapidly growing, due to the importance of preen oil for many aspects of avian life. Microbial DNA extractions from avian fecal and preen oil samples present multiple challenges, however. Here, we describe a modified PrepMan Ultra Sample Preparation Reagent microbial DNA extraction method that is less expensive than other commonly used methodologies and is highly effective for both fecal and preen oil samples collected from a broad range of avian species. We expect our method will facilitate microbial DNA extractions from multiple avian microbiome reservoirs, which have previously proved difficult and expensive. Our method therefore increases the feasibility of future studies of avian host microbiomes.

Analytical characterization of volatiles present in the whole body odour of zebra finches

In recent decades, the compositions of preen oil and feathers have been studied to achieve insights into the chemistry of avian odours, which play a significant role in birds’ social behaviour. Fewer studies are available regarding volatiles originating from other sources, such as faeces, eggs or a bird’s whole body. The aims of this study were (i) to identify odour-active and further volatile compounds in zebra finch whole body odour and (ii) to semi-quantify selected volatiles and use the information to evaluate two different adsorbents for their suitability for whole body odour sampling. Volatiles from the headspace above zebra finches were sampled using an open loop system equipped with either activated charcoal or Tenax® TA. Samples were analysed by olfactory-guided approaches as well as gas chromatography–mass spectrometry. Using activated charcoal as sorbent, 26 odour-active and 73 further volatile compounds were detected, whereas with Tenax® TA 27 odour-active and 81 further volatile compounds were detected. In total, 104 compounds were (tentatively) identified, of which 22 had not been identified previously in zebra finch odour and 12 had not been described in any birds. Hints towards a chemical sex signature became evident for qualitative but not for quantitative differences. With the exception of some compounds, notably carboxylic acids and alkanes, relative peak areas obtained with the two adsorbent types were comparable. The approach described herein is proposed for future studies aiming to determine volatiles emitted by birds when, for example, parent birds are approaching the nest.Graphical

No sex difference in preen oil chemical composition during incubation in Kentish plovers.

Preen oil, the secretion from the uropygial gland of birds, may have a specific function in incubation. Consistent with this, during incubation, the chemical composition of preen oil is more likely to differ between sexes in species where only one sex incubates than in species where both sexes incubate. In this study, we tested the generality of this apparent difference, by investigating sex differences in the preen oil composition of a shorebird species, the Kentish plover (Anarhynchus, formerly Charadrius, alexandrinus). As both sexes incubate in this species, we predicted the absence of sex differences in preen oil composition during incubation. In the field, we sampled preen oil from nine females and 11 males during incubation, which we analysed with gas chromatography-mass spectrometry (GC-MS). Consistent with predictions, we found no sex difference in preen oil composition, neither in beta diversity (Bray-Curtis dissimilarities) nor in alpha diversity (Shannon index and number of substances). Based on these results, we cannot conclude whether preen oil has a function during incubation in Kentish plovers. Still, we discuss hypothetical roles, such as olfactory crypsis, protection against ectoparasites or olfactory intraspecific communication, which remain to be tested.

Apparent anti‐parasite behaviour in the Norfolk Island green parrot Cyanoramphus cookii

AbstractBirds must cope with all manner of ectoparasites, from insects and mites to bacteria and fungi. During their grooming routine, several Norfolk Island green parrots Cyanoramphus cookii were observed and photographed, and a pair was videoed, biting off and chewing small pieces of lateral shoot and bark of pepper trees Piper excelsum and working the chewed material through their feathers. They also stripped the leaves and rubbed their beaks along the branches before extracting preen oil. Pepper trees are a well‐known source of piperine and other potent aromatic chemicals that are insect repellent and antimicrobial. This appears to be a rare example of a bird using plant material to anoint themselves, which we interpret as a way to repel blood‐sucking insects and ectoparasites and, possibly, void endoparasites, thereby improving fitness.

Chemical Profiles Differ between Communal Breeding Groups in a Highly Social Bird.

AbstractGregarious species must distinguish group members from nongroup members. Olfaction is important for group recognition in social insects and mammals but rarely studied in birds, despite birds using olfaction in social contexts from species discrimination to kin recognition. Olfactory group recognition requires that groups have a signature odor, so we tested for preen oil and feather chemical similarity in group-living smooth-billed anis (Crotophaga ani). Physiology affects body chemistry, so we also tested for an effect of egg-laying competition, as a proxy for reproductive status, on female chemical similarity. Finally, the fermentation hypothesis for chemical recognition posits that host-associated microbes affect host odor, so we tested for covariation between chemicals and microbiota. Group members were more chemically similar across both body regions. We found no chemical differences between sexes, but females in groups with less egg-laying competition had more similar preen oil, suggesting that preen oil contains information about reproductive status. There was no overall covariation between chemicals and microbes; instead, subsets of microbes could mediate olfactory cues in birds. Preen oil and feather chemicals showed little overlap and may contain different information. This is the first demonstration of group chemical signatures in birds, a finding of particular interest given that smooth-billed anis live in nonkin breeding groups. Behavioral experiments are needed to test whether anis can distinguish group members from nongroup members using odor cues.

Volatile organic compounds in preen oil and feathers - a review.

For a long time birds were assumed to be anosmic or at best microsmatic, with olfaction a poorly understood and seldom investigated part of avian physiology. The full viability of avian olfaction was first discovered through its functions in navigation and foraging. Subsequently, researchers have investigated the role of olfaction in different social and non-social contexts, including reproduction, kin recognition, predator avoidance, navigation and foraging. In parallel to the recognition of the importance of olfaction for avian social behaviour, there have been advances in the techniques and methods available for the sampling and analysis of trace volatiles and odourants, leading to insights into the chemistry underlying chemical communication in birds. This review provides (i) an overview of the current state of knowledge regarding the volatile chemical composition of preen oil and feathers, its phylogenetic coverage, chemical signatures and their potential functions, and (ii) a discussion of current methods used for the isolation and detection of volatiles. Finally, lines for future research are proposed.

The smell of zebra finches: Elucidation of zebra finch odour applying gas chromatography-mass spectrometry and olfaction-guided approaches

Zebra finches use volatile compounds for olfactory communication. In this study the volatile composition of zebra finch preen oil and feathers, potential sources of semiochemicals, was studied applying olfactory-guided approaches. In sum, 14 sample pools consisting of 1600 individual samples were analysed. In preen oil, 34 odour-active and 75 further volatiles were detected. In feathers, 51 odour-active and 76 further volatiles were detected. Several substances were common to both sample types, and feathers beared a higher number of volatiles than preen oil. We found hints towards a sex chemical signature. In sum, 121 compounds were identified, out of which 95/49 compounds had not been described in zebra finches/in birds before. This study shows that the combination of classic gas chromatography - mass spectrometry with olfaction-guided approaches leads to a more comprehensive characterization of the avian volatilome. The here presented approach can also be applied for other species.

Preen oil composition of Pied Flycatchers is similar between partners but differs between sexes and breeding stages

Preen oil, the secretion of the uropygial gland, may be an important source of body odour in birds. By characterizing the chemical composition of preen oil, we can describe the olfactory phenotypes of birds and investigate whether odours could have a function in sexual signalling or other chemical communication. Here we analysed the preen oil of a wild passerine, the European Pied Flycatcher Ficedula hypoleuca, to find out whether it holds socially relevant information. We sampled both the female and male of breeding pairs during nestling rearing to test for sex differences and within‐pair similarity. We additionally sampled the females during incubation to test for changes across breeding stages and for individual repeatability of chemical profiles. Pair mates had similar chemical profiles in comparison with other breeding adults. Furthermore, we found evidence for sex differences and for changes across breeding stages. Notably, the preen oil of females was more diverse and more volatile than that of males, and the preen oil secreted by females during incubation was more volatile than that secreted during nestling rearing. However, we found no evidence for individual repeatability of chemical profiles across breeding stages in females. Our results point towards a function of preen oil in sexual signalling, although other functions should not be excluded. Our study is a first step towards understanding the role of odours in the social life of an important avian model species used in the study of mate choice and sexual selection.

The penguin feather as inspiration for anti-icing surfaces

Understanding how to influence ice adhesion to structures and prevent icing catastrophes is a paramount research question. Conventional industrial anti-icing methods are active, requiring an energy source. However, active strategies are energy intensive. Passive anti-icing surfaces have thus become an area of engineering interest. Such strategies, like low surface energy chemical coatings, produce highly anti-icing surfaces on a lab-scale but they have not succeeded in industrial applications. They lack efficacy over repeated icing/de-icing cycles and their materials are unsuited for harsh environments. The body feather of the sub-Antarctic Gento penguin Pygoscelis papua, which ornithologists note is perpetually free of ice despite its freezing environment, serves as a compelling source of passive anti-icing biomimetic inspiration which may overcome these aforementioned deficiencies. Through studying these feathers, it has become clear that two aspects of anti-icing (water-shedding and ice-shedding) are addressed in distinct ways by the Gentoo penguin. The water-shedding functionality of the feathers is derived from an air cushion created by the wire-like microstructure of the feather and is augmented by nano-scale grooves in the feather coated in preen oil. The preen oil is necessary to maintain water-shedding functionality, however once removed the ice-shedding functionality of the feathers is maintained. The ice-shedding functionality appears to be derived from wire-like morphology of the penguin body feather barbs and barbules which induce cracks that are easily opened at the ice-feather interface. Such a design strategy shows promise in addressing the common failings of passive systems. These anti-icing strategies were then tested on metallic biomimetic substrates. The barb structure of the penguin body feather was mimicked using ultra-fine woven stainless-steel wire cloth. Some stainless-steel wire cloths were laser machined to mimic the texturing and surface chemistry of the feathers. These cloths were indeed hydrophobic like the feathers. Both stainless-steel wire cloths had significantly reduced ice adhesion strengths compared to those of the flat monolithic stainless-steel sample. The laser-machined wire cloth had an ice adhesion strength of 63 ± 10 kPa compared to 603 ± 236 kPa for the flat sample. This both indicates that the ice-shedding capabilities of the sample are imparted by the structure and further strengthens the argument that water-shedding and ice-shedding are distinct phenomena that need to be addressed with two separate design strategies.

Effects of short-term experimental manipulation of captive social environment on uropygial gland microbiome and preen oil volatile composition

IntroductionAvian preen oil, secreted by the uropygial gland, is an important source of volatile compounds that convey information about the sender’s identity and quality, making preen oil useful for the recognition and assessment of potential mates and rivals. Although intrinsic factors such as hormone levels, genetic background, and diet can affect preen oil volatile compound composition, many of these compounds are not the products of the animal’s own metabolic processes, but rather those of odor-producing symbiotic microbes. Social behavior affects the composition of uropygial microbial communities, as physical contact results in microbe sharing. We experimentally manipulated social interactions in captive dark-eyed juncos (Junco hyemalis) to assess the relative influence of social interactions, subspecies, and sex on uropygial gland microbial composition and the resulting preen oil odor profiles.MethodsWe captured 24 birds at Mountain Lake Biological Station in Virginia, USA, including birds from two seasonally sympatric subspecies – one resident, one migratory. We housed them in an outdoor aviary in three phases of social configurations: first in same-sex, same-subspecies flocks, then in male-female pairs, and finally in the original flocks. Using samples taken every four days of the experiment, we characterized their uropygial gland microbiome through 16S rRNA gene sequencing and their preen oil volatile compounds via GC-MS.ResultsWe predicted that if social environment was the primary driver of uropygial gland microbiome composition, and if microbiome composition in turn affected preen oil volatile profiles, then birds housed together would become more similar over time. Our results did not support this hypothesis, instead showing that sex and subspecies were stronger predictors of microbiome composition. We observed changes in volatile compounds after the birds had been housed in pairs, which disappeared after they were moved back into flocks, suggesting that hormonal changes related to breeding condition were the most important factor in these patterns.DiscussionAlthough early life social environment of nestlings and long-term social relationships have been shown to be important in shaping uropygial gland microbial communities, our study suggests that shorter-term changes in social environment do not have a strong effect on uropygial microbiomes and the resulting preen oil volatile compounds.

Halogenated flame retardant exposure pathways in urban-adapted gulls: Are atmospheric routes underestimated?

Urban-adapted gulls can be exposed to flame retardants while foraging in landfills where elevated concentrations of polybrominated diphenyl ethers (PBDEs) and other halogenated flame retardants (HFRs) have frequently been measured in air. However, the contribution of atmospheric exposure has largely been overlooked compared to dietary exposure in birds and other wildlife. The overall objective of this study was to investigate the contribution of atmospheric exposure pathways relative to diet for PBDEs and other HFRs in ring-billed gulls (Larus delawarensis) nesting in the densely populated Montreal area (QC, Canada). Miniature passive air samplers (PASs) were deployed on the back of wild-caught ring-billed gulls for ten days. Concentrations of PBDEs and other HFRs were determined in PASs carried by ring-billed gulls as well as their lungs, stomach content, liver, preen oil, and onto the surface of their feathers. We evaluated the atmospheric and dietary exposure routes for the most abundant HFRs in samples using a structural equation model implemented in a Bayesian framework. Results indicated that lung concentrations of BDE-28 increased with its levels in air determined using bird-borne PASs. No association was found between BDE-28 concentrations in lungs and liver, whereas BDE-209 concentrations in liver increased with those in lungs. Moreover, BDE-28 and -47 concentrations in liver increased with those on feather surface, while liver BDE-47 concentrations were also positively related with those in stomach content. These findings suggested that, in addition to dietary exposure, atmospheric exposure pathways through inhalation and co-ingestion during feather maintenance (preening) significantly contribute to the accumulation of PBDEs in liver of ring-billed gulls. Atmospheric exposure to HFRs should therefore be considered in future landfill-foraging wildlife species as a potential exposure route compared to the traditional dietary exposure pathway.

Symbiotic microbes play a role more important than preen gland in avian pheromone production––A review

The uropygial gland or preen gland is a complex holocrine structure present only in birds, and plays an important role in avian communication and reproduction. This gland produces preen oil, which helps birds maintain intact plumage, plumage colorage, but also possesses antibacterial and anti-predator properties, and the evidence for these claims is still in infancy. Preen gland harbour a large number of microbiota among which as many as 110 are bacterial genera dominated by Firmicutes, Proteobacteria, Bacteroidetes, etc., families, and the roles of these microbes are largely unknown. However, these microbes are believed to maintain symbiotic relationship with the host and exert positive effects in the host’s physiology and behaviour. Many studies have proven that these microbes produce chemical cues as metabolic by-products that modulate the host’s behavior. In birds, these symbiotic microbes are needed for normal growth, development and even reproduction. Earlier findings about preen gland microbiota of birds connect it to good feather condition, recent evidences connect it to antifungal and antimicrobial activities. Although preen gland plays a major role in bird’s development, symbiotic microbes of preen gland seem to play a crucial role in reproduction and pheromonal communication. Here, we review the role of microbes present in avian preen gland in production of chemical signals and document the relationship between the microbes and preen gland in chemical communication.

Nature-inspired trapped air cushion surfaces for environmentally sustainable antibiofouling

Feathers of seabirds and waterfowl (for example the mallard duck (Anas platyrhynchos)) consist of hierarchical fibrillar structures encapsulated with hydrophobic preen oil. These characteristics afford waterproofing through the entrapment of air pockets, enabling swimming and diving for such bird species. This liquid repellency mechanism for bird feathers is mimicked by surface hydrophobisation of fibrous nonwoven polypropylene textiles to create large volumes of trapped air at the solid–liquid interface (plastron). Higher static water contact angle values correlate to a greater resistance towards water ingress (akin to the behaviour of mallard feathers). In order to extend the trapped gas layer lifetimes, the transportation of air from the water surface to a submerged air bubble by the diving bell spider (Argyroneta aquatica) for respiration is mimicked via short duration (< 1 s) solar-powered air bubble bursts once every 2 h. This combination of ornithological and arachnological inspired approaches yields stable trapped gas layers at the solid–liquid interface which are shown to inhibit biofouling in real-world outdoor wet environments.

​​Comparative Micro and Macro Anatomical Observation on Preen Gland of Kamrupa (Gallus domesticus), White Leg Horn (Gallus domesticus) and Daothigir Fowl (Gallus domesticus) of Assam

Background: The study on the preen gland of Kamrupa, White leg horn and Daothigir fowl of Assam is of great value in regard to protection of skin and feather of avian species. The aim of this study was to evaluate the micro and macro anatomical observation of preen gland of integument system. Methods: The present study was conducted on the preen gland of fifteen healthy, adult birds of Kamrupa, White leg horn and Daothigir fowl of Assam in Department of Anatomy and Histology, College of Veterinary Science, Assam Agricultural University, Khanapara, Guwahati, Assam, India for period of one year from 2020-2021. Those fowl were procured from different parts of Assam. The birds were sacrificed according to the method of Gracy (1968). After sacrifice, preen gland were removed very carefully from the base of the tail of fowl. After collection, the tissue samples were fixed in 10% neutral buffered formalin solution, and were processed as per the standard technique of procedure (Luna, 1968). The paraffin blocks were sectioned in Shandon Finesse microtome at 5 µm thickness and the sections were stained with Mayer’s Haematoxylin and Eosin staining technique for Cellular details as per the standard method of Luna (1968). Result: In present investigation, it was observed that, macroscopically, the preen gland or oil gland or rump gland or uropygial gland of Kamrupa, White leg horn and Daothigir fowl of Assam was situated on the dorsal aspect of the base of the tail. Microscopically, the preen gland of Kamrupa, White leg horn and Daothigir fowl of Assam was bounded by connective tissue capsule. The interlobular connective tissues were observed among the secretary tubules of the gland. The preen gland parenchyma composed of secretary tubules; duct that formed trabeculae, which were differentiated by inter tubular connective tissue.

Songbird preen oil odour reflects haemosporidian parasite load

Investigating the impact of parasitism on host phenotype is key to understanding parasite transmission ecology, host behavioural ecology and host-parasite coevolution. Previous studies have provided evidence that avian odour is one such phenotypic trait, as mosquitoes that vector the haemosporidian blood parasite Plasmodium tend to prefer birds that are already infected. Preen oil is a major source of avian odour, yet studies to date have not identified differences in preen oil odour based on the presence or absence of haemosporidian infection. Because preen oil can vary with physiological dynamics, we predicted that the composition of preen oil odours might vary according to parasite load, rather than solely by the presence or absence of infection. We used gas chromatography-mass spectrometry to characterize the composition of volatile compounds in preen oil taken from female dark-eyed juncos, Junco hyemalis carolinensis, and asked whether their composition varied with relative haemosporidian parasite load, which we assessed using quantitative PCR. We identified a subset of volatile compounds (a 'blend') and two specific compounds that varied with increasing parasite load. Importantly, the quantity of these compounds did not vary based on parasite presence or absence, suggesting that birds with low parasite loads might be phenotypically indistinguishable from uninfected birds. The volatile blend associated with parasite load also varied with sampling date, suggesting a possible seasonal relapse of chronic infections triggered by shifts in junco host reproductive state. Furthermore, we found a positive relationship between parasite load and a volatile blend shown in a previous study to predict reproductive success in juncos. This is the first study to demonstrate quantitative differences in avian host odour based on haemosporidian parasite load. Our findings highlight the importance of focusing on parasite load, rather than solely presence or absence, in investigating host-parasite interactions.

Made-up mouths with preen oil reveal genetic and phenotypic conditions of starling nestlings.

Animal coloration results from pigments, nanostructures, or the cosmetic use of natural products, and plays a central role in social communication. The role of cosmetic coloration has traditionally been focused in scenarios of sexual selection, but it could also take place in other contexts. Here, by using spotless starlings (Sturnus unicolor) as a model system, we explore the possibility that nestlings cosmetically use their intensely yellow-colored uropygial secretion to signal their genetic and/or phenotypic quality. In agreement with the hypothetical cosmetic use of the uropygial secretion, (i) video recorded nestlings collected secretion with the bill at the age of feathering, (ii) cotton swabs turned to the color of secretion after rubbing with them nestlings’ gape, and (iii) gape and skin colorations correlated positively with that of secretion. Furthermore, we found that (iv) secretion coloration has a genetic component, and (v) associated positively with Vitamin E supplementation and (vi) with plasma carotenoid concentration, which highlights the informative value of nestling secretion. Finally, (vii) coloration of begging-related traits and of secretion of nestlings predicted parental feeding preferences. Consequently, all these results strongly suggest that the cosmetic use of colored uropygial secretion might also play a role in parent-offspring communication, complementing or amplifying information provided by the flamboyant colored gapes and skin of nestlings. The use of makeups by offspring for communication with relatives has been scarcely explored and we hope that these results will encourage further investigations in birds and other taxa with parental care.

Feathers as an integrated measure of organohalogen contamination, its dietary sources and corticosterone in nestlings of a terrestrial bird of prey, the northern Goshawk (Accipiter gentilis)

In this study, we evaluated the suitability of body feathers, preen oil and plasma for estimation of organohalogen compound (OHC) exposure in northern goshawk Accipiter gentilis nestlings (n = 37; 14 nests). In addition, body feathers received further examination concerning their potential to provide an integrated assessment of (1) OHC exposure, (2) its dietary sources (carbon sources and trophic position) and (3) adrenal gland response (corticosterone). While tetrabromobisphenol A was not detected in any sample, the presence of polychlorinated biphenyls, organochlorine pesticides, polybrominated diphenyl ethers and hexabromocyclododecane in body feathers (median: 23, 19, 1.6 and 3.5 ng g−1 respectively), plasma (median: 7.5, 6.2, 0.50 and 1.0 ng g−1 ww, respectively) and preen oil (median: 750, 600, 18 and 9.57 ng g−1 ww, respectively) suggests analytical suitability for biomonitoring of major OHCs in the three matrices. Furthermore, strong and significant associations (0.20 ≤ R2 ≤ 0.98; all P < 0.05) among the OHC concentrations in all three tissues showed that body feathers and preen oil reliably reflect circulating plasma OHC levels. Of the dietary proxies, δ13C (carbon source) was the most suitable predictor for variation in feather OHCs concentrations, while no significant relationships between body feather OHCs and δ15N (trophic position) were found. Finally, body feather corticosterone concentrations were not related to variation in OHC concentrations. This is the first study to evaluate feathers of a terrestrial bird of prey as an integrated non-destructive tool to jointly assess nestling ecophysiology and ecotoxicology.

Olfactory camouflage and communication in birds.

Smell is a sensory modality that is rarely considered in birds, but evidence is mounting that olfaction is an important aspect of avian behaviour and ecology. The uropygial gland produces an odoriferous secretion (preen oil) that can differ seasonally and between the sexes. These differences are hypothesized to function in olfactory camouflage, i.e. minimizing detection by nest predators (olfactory crypsis hypothesis), and/or intraspecific olfactory communication, particularly during breeding (sex semiochemical hypothesis). However, evidence for seasonal and sex differences in preen oil is mixed, with some studies finding differences and others not, and direct evidence for the putative function(s) of seasonal variation and sex differences in preen oil remains limited. We conducted a systematic review of the evidence for such changes in preen oil chemical composition, finding seasonal differences in 95% of species (57/60 species in 35 studies) and sex differences in 47% of species (28/59 species in 46 studies). We then conducted phylogenetic comparative analyses using data from 59 bird species to evaluate evidence for both the olfactory crypsis and sex semiochemical hypotheses. Seasonal differences were more likely in the incubating than non-incubating sex in ground-nesting species, but were equally likely regardless of incubation strategy in non-ground-nesting species. This result supports the olfactory crypsis hypothesis, if ground nesters are more vulnerable to olfactorily searching predators than non-ground nesters. Sex differences were more likely in species with uniparental than biparental incubation and during breeding than non-breeding, consistent with both the olfactory crypsis and sex semiochemical hypotheses. At present, the data do not allow us to disentangle these two hypotheses, but we provide recommendations that will enable researchers to do so.

Biosafe Management of Botrytis Grey Mold of Strawberry Fruit by Novel Bioagents.

Recently, there have been urgent economic and scientific demands to decrease the use of chemical fungicides during the treatment of phytopathogens, due to their human health and environmental impacts. This study explored the biocontrol efficacy of novel and eco-friendly preen (uropygial) oil and endophytic Bacillus safensis in managing postharvest Botrytis grey mold in strawberry fruit. The preen oil (25 μL/mL) showed high antifungal activity against B. cinerea Str5 in terms of the reduction in the fungal radial growth (41.3%) and the fungal colony-forming units (28.6%) compared to the control. A new strain of Bacillus safensis B3 had a good potential to produce chitinase enzymes (3.69 ± 0.31 U/mL), hydrolytic lipase (10.65 ± 0.51 U/mL), and protease enzymes (13.28 ± 0.65 U/mL), which are responsible for the hydrolysis of the B. cinerea Str5 cell wall and, consequently, restrict fungal growth. The in vivo experiment on strawberry fruit showed that preen (uropygial) oil reduced the disease severity by 87.25%, while the endophytic bacteria B. safensis B3 reduced it by 86.52%. This study reports the efficiency of individually applied bioagents in the control of phytopathogenic fungi for the first time and, consequently, encourages their application as a new and innovative strategy for prospective agricultural technology and food safety.