Journal of Threatened Taxa |
www.threatenedtaxa.org | 26 June 2022 | 14(6): 21161–21169
ISSN 0974-7907 (Online) | ISSN 0974-7893
(Print)
https://doi.org/10.11609/jott.7936.14.6.21161-21169
#7936 | Received 27 March 2022 | Final
received 01 May 2022 | Finally accepted 10 June 2022
Feather characteristics of Common
Myna Acridotheres
tristis (Passeriformes: Sturnidae)
from India
Swapna Devi Ray 1,
Goldin Quadros 2, Prateek Dey 3, Padmanabhan Pramod 4 & Ram Pratap Singh 5
1,3,4,5 National Avian Forensic
Laboratory, 2 Wetland Ecology Division,
Sálim Ali Centre for Ornithology and
Natural History, Anaikatty, Coimbatore, Tamil Nadu
641108, India.
1,3 Bharathiar University, Coimbatore, Tamil
Nadu 641046, India.
5 Department of Life Science,
School of Earth, Biological and Environmental Sciences, Central University of
South Bihar, Gaya,
Bihar 824236, India.
1 swapnadray555@gmail.com, 2 goldinq@gmail.com,
3 pratikdey23@gmail.com, 4 neosacon@gmail.com,
5 rampratapsingh81@gmail.com
(corresponding author)
Abstract: The systematic study of feather
microstructure supports species identification, which is important in cases of
illegally traded birds and bird-aircraft strikes. Our study focused on
morphometric, macro- and micro-characters of feathers of Common Myna Acridotheres tristis from India. Among macro-characters, silver-colored filoplume feathers with
pale black pigmentation on the barbs are specific for A. tristis.
Morphometric measurements revealed that primary contour feathers (10.8±0.100
cm) were the longest and bristle feathers (1.26±0.051 cm) the shortest among
all feathers. The longest (average) barb is found in primary contour feathers
(1.875±0.123 cm), and the shortest in filoplume
feathers (0.288±0.017 cm). We observed 3 types of nodal structures, and elongated
prongs in bristle and filoplume feathers are
significant characteristics of A. tristis.
These insights into feather microstructures of A. tristis
will aid species identification using plumology.
Keywords: Micro-structure, macro-structure,
morphometry, plumology, Sturnidae.
Editor: P.A. Azeez, Coimbatore, Tamil
Nadu, India. Date of publication: 26 June 2022
(online & print)
Citation: Ray, S.D., G. Quadros, P. Dey, P. Pramod &
R.P. Singh (2022). Feather characteristics of Common
Myna Acridotheres
tristis (Passeriformes: Sturnidae)
from India. Journal of
Threatened Taxa 14(6): 21161–21169. https://doi.org/10.11609/jott.7936.14.6.21161-21169
Copyright: © Ray et al. 2022. Creative Commons Attribution
4.0 International License. JoTT allows unrestricted use, reproduction, and
distribution of this article in any medium by providing adequate credit to the
author(s) and the source of publication.
Funding: This work was supported by the
Ministry of Environment, Forest and Climate Change (MoEFCC).
Competing interests: The authors
declare no competing interests.
Author details: Swapna Devi Ray is doctoral student of Bharathiar University, Coimbatore and affiliated to SACON.
She is a researcher from ecology and environmental Science background. For her
doctoral degree she is working on wildlife crime, plumology
and molecular markers of avian species at National Avian Forensic Laboratory,
SACON. Dr.
Goldin Quadros is working as Principal
Scientist at the Wetland Ecology Division of SACON. His area of specialization
is the benthic fauna from the intertidal regions of coasts, estuaries and
creeks. He is also working as the coordinator of ENVIS Centre at SACON. Prateek
Dey is a doctoral student of Zoology (Avian
Genetics) at SACON. He has Integrated MSc in life sciences from Central
University of Tamil Nadu. Currently he is working on whole genome sequencing of
birds. Dr. Padmanabhan Pramod is a
Senior Principal Scientist and head of Nature Education programme
at SACON. Over a period of 27 years he has carried out variousresearch
projects in the field of ecosystem assessments, eco-development and mitigation
measures for the bird hazards to aircrafts. Dr.
Ram Pratap Singh is Associate Professor and Head, Department of Life
Science at Central University of South Bihar. The primary focus of Dr. Singh’s
research is Avian Genetics and Avian Forensic. He established the National
Avian Forensic Laboratory and started the Genome Resource Bank at SACON.
Author contributions: S.D.R. collected the sample;
R.P.S., G.Q. and P.P. conceived the idea and supervised the research; R.P.S.,
and P.P. generated the funds for the study. S.D.R, G.Q., P.D. and R.P.S.
standardized the methodology; S.D.R. generated the data. S.D.R., G.Q. and
R.P.S. wrote the manuscript and analyzed the data. All the authors reviewed the
manuscript.
Acknowledgements: We are thankful to the Ministry
of Environment, Forest and Climate Change (MoEFCC)
for providing funding to the project. We thank to the Assam Forest Department
and the Assam State Biodiversity Board for providing necessary permissions. We
are greatly thankful to the field assistance Mr. Niren
Singh for his assistance during field works in Assam.
Introduction
Feathers cover the body of birds
(Gill 2007) and support their survival in a wide range of climatic conditions (Lovette & Fitzpatrick 2016). The study of the
microscopic structures of feathers and their systematic description (i.e., plumology) has provided a useful tool in studies of bird
evolution (Chandler 1916; Dove 1997), paleontology, archeology, ecology (e.g., examining feeding habits using
prey remains) and in the forensic examination of bird strikes (Dove 1997),
where feather microstructures support the identification of avian species
(Chandler 1916; Lei et al. 2002; Dey et al. 2021). In
India only a few recent plumology studies (Dey et al. 2021; Ray et al. 2021) have been reported.
The Common Myna
Acridotheres tristis
belongs to the family Sturnidae, and is widely
distributed across the Indian subcontinent. It is a medium-sized (~25 cm) bird,
with no distinct sexual dimorphism (Ali & Ripley 1987; Kannan & James
2020). It is one of the world’s most invasive species as per IUCN (Lowe et al.
2004), and according to Ahmed (2001), A. tristis
is among the top five most traded avian species in Indian pet markets and in
the illegal pet/avian trade (Ahmed 1997, 2013). A. tristis
is sold at a high price in both domestic and international illegal pet
markets as Hill Myna Gracula
religiosa by disguising its appearance with
slight morphological modifications (Ahmed 1997). Without detailed examination
it is difficult to distinguish these species (Ahmed, 1997; Lei et al. 2002),
and the high demand for G. religiosa in the
pet trade has put pressure on population of A. tristis.
Plumology can be used to identify these birds from
their feather microstructures (Dove 1997; Lei et al. 2002; Lee et al. 2016; Dey et al. 2021; Ray et al. 2021).
In the present study, we have
focused on the systematic approach to document qualitative and quantitative
feather characteristics of A. tristis useful
for identifying species-specific feather signatures. We describe specific
microstructures present in both pennaceous and plumulaceous
barbs that can be used as baseline data for future plumology
studies in India.
Methods
Feathers from a specimen of A.
tristis (26.60°N; 93.47°E) were collected during
a road-kill survey in September 2019 from adjacent road-stretches of Kaziranga National Park, Assam, India (Figure 1).
Permissions were obtained for the collection of avian biological samples from
the office of the Principal Chief Conservator of Forests, Assam Forest
Department (Ref. no. WL/FG.31/Pt/Technical Committee/2018) and office order
(No. 258, date: 11/01/2019) and Assam State Biodiversity Board (Ref. no:
ABB/Permission/2012/82). Feathers from the collected individuals were sampled,
and macro characteristics, microstructures and morphometric measurements were
documented following methods described by Chandler (1916), Dove (1997), and Dey et al. (2021).
Nine different types of
pennaceous and plumulaceus feathers were sampled from
five different body locations (Image 1) as follows:
Primary contour feathers and
secondary contour feathers were collected from the right wing;
Tail contour feathers were
collected from the tail region;
Body contour, semiplume,
down and powder down feathers were collected from dorsal, ventral, and tail
regions.
Modified contour feathers known
as bristle feathers were collected from specific locations near the eyes and
beak.
Filoplume feathers, which are filamentous
in structure, were retrieved from the right wing.
For primary contour, secondary
contour, tail contour, body contour, semiplume, down
and powder down types of feathers, two numbers from each type from their
respective locations were retrieved for the study. Due to the location
specificity, five each of bristle and filoplume
feathers were collected. A total of 38 different feathers were studied to
document macro characteristics and microstructures.
Based on morphometric
measurements of rachis, the feathers were divided into three different regions,
proximal, intermediate and distal, except for powder down and bristle feathers
(Dey et al. 2021). Because of the absence of proper
rachis, the powder down and bristle feathers were not divided into the three
regions. From each region, five barbs were sampled for slide preparation. Five
each of bristle and filoplume feathers were
whole-mounted on slides. The slides were prepared using the dry mount method
(Ray et al. 2021; Dey et al. 2021).
Feather macro characters were
observed by focusing on three main characters: colour, pattern and texture.
Morphometric characters were measured from feathers’ photographs for calamus
length, vane length and rachis length using imageJ
software. The feather microstructures were observed and documented using LaboMed Lx 500 compound light microscope. Slides were
observed under 4X, 10X and 40X magnification for different characters,
including presence of sub-pennaceous region, presence of villi, shape of villi,
presence of nodes, shape of nodes, presence of hooklets,
presence of prongs, size of prongs, presence of ventral teeth, shape of
internodes, pigmentation on nodes, internodes, and ramus.
Results
Feather macro characters
The feather macro characters
documented for A. tristis are presented in
Table 1. Feather color varied from black and white to
dark brown to pale white and brown, even dark brown with a tinge of white. Only
filoplume feathers showed a silvery appearance with
pale black colored barbs at the tip. The texture of
feathers varied. Flight contour feathers (primary contour, secondary contour
and tail contour feathers) and bristles that represent modified contour
feathers were firmly rigid, body contour feathers irrespective of their
location were semi-rigid, and semiplume, down and
powder down feathers were soft and fluffy.
Feather morphometry
Calamus length, vane length and
rachis length of the nine different types of feathers were measured (Table 2).
The primary contour feather from the wing was the longest; the average length
for the calamus was 1.45±0.050 cm, vane length 9.35±0.050 cm and rachis
10.8±0.100 cm. Bristles were the shortest feathers, with an average calamus
length of 0.26±0.024 cm, average vane length of 1±0.032 cm and average rachis
length of 1.26±0.051 cm. The vane and rachis length was not measured for powder
down due to the absence of rachis. As there was no quill present in filoplume, only the feather and barb lengths were measured.
The average length of barbs was
measured. The longest feather type i.e. primary contour feathers followed with
the longest barbs measured as 1.875±0.123 cm while the barbs of filoplume feathers measured as the shortest with
0.288±0.017 cm.
Feather microstructures
The barbs from the nine different
feather types of A. tristis were dry-mounted
onto slides to observe different microstructures (Table 3) under the microscope
that included elongated barbules, distinct nodes, internodes, sub-pennaceous
region, villi, prongs, hooklets, ventral teeth,
pigmentation and other focused microstructures, elaborated below.
Sub-pennaceous region: The barbs of all the feathers
showed the absence of a sub-pennaceous region in both pennaceous and plumulaceous barbules in all feather types.
Villi: Villi are
the unique diagnostic microstructural characteristic of passerine birds that
extend out from the basal cell of the barbules, only present in the basal cell
region of the plumulaceous barbs. The shape of villi
was either knobbed or pointed, but sometimes both were present in the basal
cells forming finger-like structures (Image 2A–B).
Nodes and
their shape: The barbules of all feathers had nodes that were swollen, with three
different shapes: plain nodes (Image 2C–D), plain pronged nodes (Image 2E–F)
and quadrilobed nodes (Image 2G–H). The plumulaceous
barbs have all three node types, which were absent in pennaceous barbs. The
quadrilobed nodes were mainly present in the proximal region of barbules (Image
2), while the distal region had plain nodes either with prongs or without
prongs. These nodes were present in all the different feather types, except in
powder down, bristle and filoplume feathers.
Internode
shape: The region between two nodes is the internode, which is straight in
shape and present in the barbules of plumulaceous
barbs (Image 2C–H).
Prongs and
their size: Prongs are present only on the swollen nodes. Nodes with small prongs
were present in the plumulaceous barbs of primary
contour, secondary contour, tail contour, body contour, semiplume
and down feathers. On the nodes of the bristle (Image 2I–J) and filoplume (Image 3K–L) feathers, elongated and large-sized
prongs are present. Prongs were totally absent in powder down feathers.
Hooklets: Distinct hooklets
were present in pennaceous barbs of primary contour, secondary contour and tail
contour feathers, and were present after the basal cells of the barbules (Image
3M–N). Hooklets were completely absent in all plumulaceous barbs of A. tristis.
Ventral
teeth: Pennaceous barbs had ventral teeth at the end of basal cells that were
less broadened (Image 3O–P).
Pigmentation: Dark pigmentation was mainly
present on the nodes where internodes mostly had patchy pigmentation. However,
in the semiplume and powder down feathers, nodes had
both types of pigmentation (Image 3S–T). Ramus was present with both patchy
(Image 3Q) and dark pigmentation (Image 3R).
Discussion
In this study we have documented
feather macro-characters, morphometry and microstructures of A. tristis. The colour and texture of feathers mainly
depends on their location in the body, and also their functional aspects (Ray
et al. 2021). According to Chandler (1916), colour is the most important
characteristic in species identification, and we observed silver-colored filoplume feathers with
pale black pigmentation on the barbs as a specific character of A. tristis. It must be noted, however, that it is
difficult to retrieve filoplume feathers due to their
location and almost transparent nature.
Except for the filoplume feathers, we recorded
varying colors specific to feather types.
The texture of feathers is known
to vary based on their body location and functions, such as flight,
thermoregulation, signaling and protection (Lovette & Fitzpatrick 2016). The texture of the
feathers of A. tristis mainly comprised of
three types: rigid, semi-rigid, and soft and fluffy, associated with flight,
protection and thermoregulation respectively. While macro characteristics and
morphometric measurements tend to vary according to bird age and sex, the
measurements are species-specific (Dove 2000; Lee et al. 2015). Data on feather
morphometry can also provide clues about physical size (Lee et al. 2015). The
present study provides ranges for feather morphometry of A. tristis that can be used for these purposes.
Several studies have examined the
variation of diagnostic feather features among species, and among different
feathers (Chandler 1916; Dey 1966; Robertson et al.
1984; Brom 1991; Dove 2000; Dove & Peurach 2002; Lee et al. 2015; Dey
et al. 2021; Ray et al. 2021). These studies illustrate that the feather
microstructures of a species remain the same irrespective of individual
variation (Dove 1997; Lee et al. 2015; Ray et al. 2021). To identify passerine
birds, Chandler (1916) stated that the pennaceous barbs would contain three to
four hooklets, while Lee et al. (2015) observed the
presence of the broadened shape of ventral teeth in A. tristis.
However, Lee et al. (2015) cautioned that these microstructures cannot be
used as an exclusive character for the identification of species, while Dove
(2000) suggested that pigmentation patterns provide diagnostic clues for
determining species groups. From our study of A. tristis
feathers, we observed that there is no particular uniform pigmentation pattern
present in nodes, internodes, and ramus. However, the presence of dark and
patchy pigmentation on different shapes of nodes can be used as a micro
character for the identification of A. tristis.
Also from this study we report three microstructures that can be used in the
identification of A. tristis species: (i) the presence of finger-like villi that are distinctively
knobbed and pointed on the border of the basal cells, (ii) the presence of all
three types of nodes: quadrilobed, pronged and plain, and (iii) the presence of
sharply pointed pronged nodes on bristle and filoplume
feathers.
Conclusion
Plumology uses feather macro characters,
morphometry, and microstructures to aid the identification of order, family and
species of birds. During our study we used a systematic approach towards
identification of A. tristis. Macro-characters
including filoplume feathers helped to identify this
as a passerine species, while examination of microstructures including
finger-like projection of villi, the presence of three node types and the
presence of elongated prongs on the nodes of bristle and filoplume
feathers were identified as specific to A. tristis.
This study provides feather morphometry measurements for future reference as a
baseline for the identification of A. tristis from
India.
Table 1. Feather
macro-characteristics.
|
Feather type |
Feather location |
Color |
Pattern |
Texture |
1 |
Primary contour feather |
Wing |
Black and white |
No Pattern |
Rigid |
2 |
Secondary contour feather |
Wing |
Dark brown |
No Pattern |
Rigid |
3 |
Tail contour feather |
Tail |
Dark brown with white tinge |
No Pattern |
Rigid |
4 |
Body Contour |
Dorsal |
Pale brown |
No Pattern |
Semi-rigid |
5 |
Body Contour |
Ventral |
Pale brown |
No Pattern |
Semi-rigid |
6 |
Semiplume |
Dorsal |
Pale brown |
No Pattern |
Soft and fluffy |
7 |
Semiplume |
Ventral |
Pale brown |
No Pattern |
Soft and fluffy |
8 |
Semiplume |
Tail |
White |
No Pattern |
Soft and fluffy |
9 |
Down |
Dorsal |
Pale brown |
No Pattern |
Soft and fluffy |
10 |
Down |
Ventral |
Pale white |
No Pattern |
Soft and fluffy |
11 |
Down |
Tail |
Pale white |
No Pattern |
Soft and fluffy |
12 |
Powder Down |
Dorsal |
White |
No Pattern |
Soft and fluffy |
13 |
Powder Down |
Ventral |
White |
No Pattern |
Soft and fluffy |
14 |
Powder Down |
Tail |
White |
No Pattern |
Soft and fluffy |
15 |
Bristle |
Near Eye and Beak |
Black |
No Pattern |
Rigid |
16 |
Filoplume |
Wings |
Silver |
No Pattern |
Soft |
Table 2. Feather morphometric
measurements.
|
Feather type |
Feather location |
Length (in
cm) |
|||
Calamus ±
S.E. |
Vane ± S.E. |
Rachis ±
S.E. |
Barb ± S.E. |
|||
1 |
Primary contour feather |
Wing |
1.45±0.050 |
9.35±0.050 |
10.8±0.100 |
1.875±0.123 |
2 |
Secondary contour feather |
Wing |
1.35±0.050 |
7.80±0.000 |
9.25±0.050 |
1.821±0.111 |
3 |
Tail contour feather |
Tail |
0.8±0.100 |
7.3±0.100 |
8.25±0.050 |
1.637±0.079 |
4 |
Body contour |
Dorsal |
0.2±0.000 |
3.85±0.050 |
4.25±0.050 |
1.391±0.026 |
5 |
Body contour |
Ventral |
0.35±0.050 |
4.85±0.050 |
5.25±0.050 |
1.646±0.043 |
6 |
Semiplume |
Dorsal |
0.35±0.050 |
3.40±0.100 |
3.80±0.100 |
1.532±0.033 |
7 |
Semiplume |
Ventral |
0.45±0.050 |
4.51±0.395 |
4.58±0.425 |
1.901±0.037 |
8 |
Semiplume |
Tail |
0.45±0.050 |
4.95±0.150 |
5.50±0.100 |
1.034±0.024 |
9 |
Down |
Dorsal |
0.25±0.050 |
3.15±0.050 |
3.45±0.050 |
1.415±0.068 |
10 |
Down |
Ventral |
0.3±0.000 |
3.45±0.050 |
3.70±0.100 |
1.604±0.064 |
11 |
Down |
Tail |
0.2±0.000 |
3.25±0.050 |
3.45±0.050 |
1.078±0.057 |
12 |
Powder down |
Dorsal |
0.2±0.000 |
N/A |
N/A |
1.2799±0.046 |
13 |
Powder down |
Ventral |
0.25±0.050 |
N/A |
N/A |
1.032±0.043 |
14 |
Powder down |
Tail |
0.25±0.050 |
N/A |
N/A |
0.765±0.028 |
15 |
Bristle |
Near Eye and Beak |
0.26±0.024 |
1±0.032 |
1.26±0.051 |
0.316±0.008 |
16 |
Filoplume |
Wings |
N/A |
N/A |
1.94±0.262 |
0.288±0.017 |
Table 3. Feather microstructures.
|
Feather type |
Feather location |
Villi |
Villi shape |
Nodes |
Node shape |
Prongs |
Prong size |
Hooklets |
Ventral teeth |
Internode shape |
Pigmentation |
||
0/1 |
KNB/PNT |
0/1 |
2,3,4 |
0/1 |
S/L |
0/1 |
0/1 |
STR/KNK |
Nodes |
Internodes |
Ramus |
|||
1 |
Wing Feather |
Right Wing |
1 |
KNB, PNT |
1 |
2, 3 |
1 |
S |
1 |
1 |
STR |
6 |
5 |
6 |
2 |
Tail Contour |
Tail |
1 |
KNB, PNT |
1 |
2, 3 |
1 |
S |
1 |
1 |
STR |
6 |
5 |
6 |
3 |
Body Contour |
Dorsal & Ventral |
1 |
KNB, PNT |
1 |
2,3,4 |
1 |
S |
1 |
0 |
STR |
6 |
5 |
5, 6 |
4 |
Semiplume |
Dorsal, Ventral & Tail |
1 |
KNB, PNT |
1 |
2,3,4 |
1 |
S |
0 |
0 |
STR |
6,5 |
5 |
5,6 |
5 |
Down |
Dorsal, Ventral & Tail |
1 |
KNB, PNT |
1 |
2,3,4 |
1 |
S |
0 |
0 |
STR |
6 |
5 |
5, 6 |
6 |
Powder Down |
Dorsal, Ventral & Tail |
1 |
KNB, PNT |
1 |
3 |
0 |
NA |
0 |
0 |
STR |
5,6 |
5 |
6 |
7 |
Bristle |
Near eye and beak |
1 |
KNB,PNT |
1 |
2 |
1 |
L |
0 |
0 |
STR |
6 |
5 |
6 |
8 |
Filoplume |
Wings |
0 |
NA |
1 |
2 |
1 |
L |
0 |
0 |
STR |
5 |
5 |
5, 6 |
0—Absent | 1—Present |
KNB—Knobbed | PNT—Pointed | 2—Plain pronged node | 3—Plain unpronged
node | 4—Quadrilobed node | S—Small | L—Large | STR—Straight | KNK—Kinked |
5—Patchy pigmentation | 6—Dark pigmentation | NA—Not applicable.
For figure &
images - - click here for full PDF
References
Ali, S. &
S.D. Ripley (1987). Handbook of the birds of India and Pakistan. Vol. 5. Oxford University Press, Bombay,
278 pp.
Ahmed, A.
(1997). Live Bird
Trade in Northern India. TRAFFIC India, New Delhi, 104pp.
Ahmed, A.
(2001). Fraudulence
in Indian live bird trade: An identification monograph for control of illegal
trade. TRAFFIC
India, New Delhi, 24 pp.
Ahmed A.
(2013). ‘WILDLIFE ON
SALE’: An insight into the Sonepur Mela, Bihar. TRAFFIC POST 17: 16.
Brom, T. (1991). The diagnostic and phylogentic significance of feather structures. PhD Thesis.
Universiteit van Amsterdam, Instituutvoor
Taxonomische Zoölogie,
University of Amsterdam, viii+277 pp.
Chandler,
A.C. (1916). A study
of Feathers, with reference to their taxonomic significance. University of
California Press, Berkeley, 274 pp.
Day, M.G.
(1966).
Identification of hair and feather remains in the gut
and faeces of stoats and weasels. Journal of Zoology 148(2): 201–
217. https://doi.org/10.1111/j.1469-7998.1966.tb02948.x
Dove, C.J.
(1997). Quantification
of Microscopic Feather Characters
Used in the Identification of North American Plovers. The Condor
99(1): 47–57.
Dove, C.J.
(2000). A
Descriptive and Phylogenetic Analysis of Plumulaceous
Feather Characters in Charadriiformes. Ornithological
Monograph 51: 1-–163.
Dove, C.J.
& S.C. Peurach (2002). Microscopic Analysis of Feather
and Hair Fragments Associated with Human Mummified Remains from Kagamil Island, Alaska. To the Aleutians and
Beyond-The Anthropology of William S. Laughlin. Ethnographical Series
20: 51–62.
Dey, P., S.D. Ray, S.K. Sharma, P.
Pramod & R.P. Singh (2021).Identification of a unique barb from the dorsal body
contour feathers of the Indian Pitta Pitta brachyura (Aves: Passeriformes: Pittidae).
Journal of Threatened Taxa 13(8): 19029–19039. https://doi.org/10.11609/jott.6362.13.8.19029-19039
Gill, F.B.
(2007). Ornithology. Third Edition, W.H. Freeman and
Company, New York City, 725 pp.
Kannan, R.
& D.A. James (2020). Common Myna (Acridotheres
tristis), version 1.0. In; Billerman,
S.M. (ed.). Birds of the World. Cornell Lab of Ornithology, USA. https://doi.org/10.2173/bow.commyn.01
Lei, F.M.,
Y.H. Qu, Y.L. Gan, A. Gebauer & M. Kaiser (2002).The feather microstructure of
Passerine sparrows in China. Journal für Ornithologie 143(2): 205–212.
Lowe, S., M.
Browne, S. Boudjelas & M. De Poorter
(2004). 100 of the
World’s Worst Invasive Alien Species – A Selection from the Global Invasive
Species Database. Invasive Species Specialist Group (Species Survival Commission) of the
World Conservation Union (IUCN), 12 pp.
Lee, J., S.D.
Sarre, L. Joseph & J. Robertson (2016). Microscopic characteristics of
the plumulaceous feathers of Australian birds: a
preliminary analysis of taxonomic discrimination for forensic purposes. Australian
Journal of Forensic Sciences 48(4): 421–444. https://doi.org/10.1080/00450618.2015.107603
Lovette, I.J. & J.W. Fitzpatrick
(Eds.). (2016). Handbook of Bird Biology. John Wiley & Sons, UK, 716 pp.
Robertson,
J., C. Harkin & J. Govan (1984). The identification of bird
feathers. Scheme for feather examination. Journal of the Forensic
Science Society 24(2): 85-–98. https://doi.org/10.1016/S0015-7368
(84)72301-2
Robertson,
G.R. (2002). Birds of a
feather stick: microscopic feather residues on stone artifacts
from Deep Creek Shelter, New South Wales, pp. 175–182. Proceedings of the 2001
Australian Archaeological Assoc Annual Conference,
Tempus, Anthropology Museum, The University of Queensland.
Ray, S.D., P. Dey,
N. Islam, S.K.S. Sharma, P. Pramod & R.P. Singh (2021). Comparative study of
Yellow-billed Babbler (Turdoides affinis) feather reveals uniformity in their
microstructure among individuals. Journal of Experimental Biology and
Agricultural Sciences 9(1): 51–64. https://doi.org/10.18006/2021.9(1).51.64