Journal of Threatened Taxa |
www.threatenedtaxa.org | 26 December 2021 | 13(14): 20209–20217
ISSN 0974-7907 (Online) | ISSN 0974-7893
(Print)
https://doi.org/10.11609/jott.6631.13.14.20209-20217
#6631 | Received 27 August 2020 | Final
received 11 November 2021 | Finally accepted 08 December 2021
Roosting patterns of House
Sparrow Passer domesticus Linn., 1758 (Aves: Passeridae) in Bhavnagar, Gujarat, India
Foram P. Patel 1 & Pravinsang P. Dodia 2
1,2 Department of Zoology, Sir P.P.
Institute of Science, MKBU University, Bhavnagar, Gujarat 364002, India.
1 patelforam9795@gmail.com, 2 pravinsangdodia@gmail.com
(corresponding author)
Editor: V. Gokula,
National College, Tiruchirappalli, India. Date
of publication: 26 December 2021 (online & print)
Citation: Patel, F.P. & P.P. Dodia (2021).Roosting
patterns of House Sparrow Passer domesticus
Linn., 1758 (Aves: Passeridae) in Bhavnagar, Gujarat,
India. Journal of Threatened Taxa 13(14): 20209–20217. https://doi.org/10.11609/jott.6631.13.14.20209-20217
Copyright: © Patel & Dodia 2021. 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: None.
Competing interests: The authors
declare no competing interests.
Author details: Currently, Foram P. Patel is working as an Assistant Professor at D K V Arts
& Science College Jamnagar, Gujarat. She has recently completed her
doctorate from MKBU University, Bhavnagar, Gujarat. Her research work was
focused on analyzing the impact of anthropogenic pressures on House Sparrow
with reference to different scale of habitat in Bhavnagar, Gujarat. Her current
works focuses on exploring avian diversity across different patches of
Jamnagar, Gujarat. Dr. Pravinsang P. Dodia is
working as an Associate Professor at Sir P P Institute
of Science, MKBU University, Bhavnagar, Gujarat. His keen interest is in avian
biology.
Author contributions: FPP—conception & design of
the work, data collection, data analysis and interpretation, drafting the
article. PPD—supervisor, critical revision of the article.
Acknowledgements: We would like to express our
special thanks of gratitude to Dr. A H Shukla, head
of Zoology Department, Sir P.P. Institute of Science, Bhavnagar, for his
sincere support. Sincere thanks to P. Chudasama, D.
Solanki, J. Kanejiya, D. Kunapara,
D. Mehta, K. Tadha, D. Trivedi, K. Joshi, S. Gohel, J. Pandya, and Rajendra for assisting in field work.
We would also like to thank Dr. N. Chavada who helped us in identification of plant species.
Abstract: The House Sparrow Passer domesticus is widely distributed across the world, and
local alarming declines in sparrow populations have prompted studies focused on
this species. An understanding of fundamental life history aspects such as
roosting patterns is necessary for the development of efficient conservation
strategies. This study examined House Sparrow roosting patterns in urban,
suburban and rural areas of Bhavnagar during 2017–2018. Potential roosting
sites were identified, and peak arrival/ departure times and roosting duration
of sparrows were recorded. We found that peak arrival and departure times were
correlated with solar timings, indicating a strong influence of photoperiod on
sparrow behaviour. Little variation was observed in sparrow arrival and
departure times across the urban, suburban and rural gradient. However, arrival
duration was significantly larger in urban and suburban areas. This may be due
to the restricted availability of suitable patches within these habitats,
requiring birds to spend more time foraging. House Sparrows mostly preferred
thick vegetation for pre-roosting activities and roosting, and the loss of
thick vegetation poses a threat to sparrow populations worldwide. In addition
to increasing nesting opportunities by providing artificial nest sites, the
importance of retaining appropriate habitats should be a major focus of
conservation strategies.
Keywords: Arrival & departure pattern,
habitat, nesting, Passeriformes, pre-roosting.
Introduction
The House Sparrow Passer domesticus is one of the most widely distributed avian
species on Earth, possibly due to its adaptation to human settlements.
Nevertheless, significant declines in its populations have recently been
reported from many parts of the world (Gulati 2005). These declines have
prompted studies of sparrow breeding biology worldwide (Gokula
et al. 2014). However, key habitat needs of the species will not end by finding suitable nest sites only.
Understanding of other fundamental life history traits of the species such as
the roosting pattern is inevitable, in constructing an efficient frame work for
conservation of the species to maintain a healthy sustainable population.
Roosting can be defined as a
period of inactivity analogous to human sleep (Ehrlich et al. 1988). Roosting
is one of the fundamental life history traits of avian species. Small passerine
birds such as sparrows roost communally, which confers many probable advantages
as well as disadvantages to the birds. According to Ehrlich et al. (1988) some
species change their roosting habits seasonally: male Red-winged Blackbirds Agelaius phoeniceus,
normally roost solitarily on their territories during the breeding season, but
roost in large numbers for the rest of the year. Communal roosting in avian
populations probably helps in reducing the cost of thermoregulation and predation risk, and it is also likely to
increase foraging efficiency of the individuals (Eiserer
1984; Ydenberg & Prins
1984). According
to Ward & Zahavi (1973), roosting forms the
centre to exchange information regarding food resources. However, Erwin (1983)
opined that enhancement of food location takes place via local enhancement
rather than by information exchanged at the roost. Besides, communal roost also
provides potential mate selecting opportunities to birds lacking a partner.
However, besides possible advantages, communal roost may be energetically
costly to territorial species as they need to physically travel to and from
roosts (Beauchamp 1999). Further, a large communal roost easily attracts
potential predators due to significant vocalization (Beauchamp 1999).
Thus, the significances
of communal roosting are debatable (Richner &
Hebb 1996). The aforementioned studies, stress the importance of investigating
the roosting ecology of birds.
In the present study, an attempt
has been made to understand the roosting pattern of the sparrow across urban,
suburban and rural gradient of Bhavnagar and to identify key habitat
requirements of the species. By monitoring roosting patterns of sparrows across
different scales of habitat will shed light on understanding corresponding key habitat
requirements for healthy and efficient survival of the species. Consequently
efficient strategic plans can be framed to fulfil key habitat requirements of
the species with respect to its conservation aspects.
Study area
The present study was undertaken
in and around Bhavnagar city, Saurashtra region of Gujarat state, India.
Bhavnagar is a coastal city, with the Gulf of Khambhat located to its west. A
small non perennial river known as Kansara passes
through the outer area of the city. Bhavnagar has a hot semi
arid climate, with a hot dry summer, wet monsoon, and mild winters. Due
to the proximity of Bhavnagar to the gulf, the climate remains fairly humid
throughout the year.
To identify differential response
of the sparrow towards different scales of habitat, the study area was divided into three gradients, i.e.,
urban, suburban and rural. After a pilot survey, three potential roosting sites
were selected from each gradient by random stratified method. To avoid biases
in the data due to population mixture of different sample sites, it was ensured
that the selected sample sites were at least 2 km apart from each other – by
assuming the sedentary nature of sparrows not migrating more than 2 km (Summers
– Smith 1988). This was accomplished by creating 2 × 2 km grids over the study
area with the help of Google earth pro software, where each sample site has
been cited. Hence, nine study sites were selected to monitor roosting patterns
and population of the sparrow throughout the study period. In the current study,
within urban gradient (URB) – Barsomahadev (URB1) (21.774N,72.139E),
Bharatnagar (URB2) (21.744N, 72.160E) and Anandnagar (URB3) (21.788N, 72.157E) study sites
were selected for data collection. Within suburban gradient (SUB) – V P Society
(SUB1) ( 21.759N, 72.170E), Forest colony (SUB2) (21.737N,
72.150E) and Fulsar (SUB3) (21.746N, 72.094E)
study sites were selected for data collection. While within rural (RUR) – Akwada
(RUR1) (21.739N, 72.180E), Nari (RUR2) (21.783N,
72.077E) and Sidsar (RUR3) (21.721N, 72.110E)
study sites were selected (Image 1).
Methods
The present study was conducted
during the year December 2016 to November 2018 (24 months). For convenience,
the study period was divided into four seasons, i.e., winter
(December–February), summer (March–May), monsoon (June–August), and post
monsoon (September–November). These categories aid in understanding seasonal
variation in roosting patterns. For precise observation and data collection,
instruments like Nikon Aculon A211 8 x 42 binocular
and Nikon D500 digital SLR camera were used in the field.
In the year 2016, a pilot survey
was carried out across the study area with the aim of identifying sites with a
potential number of sparrows. Potential roosting sites were identified during
the pilot survey by following flocks of sparrows from foraging grounds in the
evening. The potential roosting sites were defined as places where more than a
hundred sparrows were found to roost frequently during the pilot survey. Avian
species, roosting together with sparrows at the same roosting plant were also
recorded. During the study period, in some cases, sparrows left the original roosting site and preferred
to roost at a different site – secondary roosting site. In these cases,
locations of the secondary roosting place was determined by following the flock
of sparrows from the original roosting site or from the foraging ground in the
evening. The approximate distance of the secondary roosting site from the
original roosting site was determined with the help of Google Earth pro
software. Further, roosting plant species used by sparrows were identified with
the help of standard field guides as well as experts in Botany. During this
study, timings of roosting sounds were also recorded. Further, peak arrival and
departure time periods along with arrival & departure durations were
recorded during each visit. Here all timings are represented in hh:mm (hour: minutes) format. Sunset and sunrise time was
noted by IST (Indian standard time, off set: UTC + 5: 30) from time and
date.com website (https://www.timeanddate.com/). To be more precise in finding
the relationship between solar movement and arrival as well as departure
pattern of House Sparrows from roosting sites, different phases of twilight
timings were also considered during the study period. A total of three twilight
timings were considered during this study, which included civil twilight
(brightest phase of twilight - enough natural light to carry out most outdoor
activities), nautical twilight (the horizon and the brighter stars are
generally visible), and astronomical twilight (darkest phase of twilight).
Statistical analysis
Data was analyzed using IBM
SPSS v.22.0 for Windows. Variance in peak arrival time, arrival duration, peak
departure time, departure duration were analysed by gradients as well as by
season using Independent-Samples Kruskal-Wallis Test – non parametric test.
Spearman rank – order correlation coefficient test was used to correlate peak
arrival and peak departure times with sunset, sun rise and day length
respectively. Significance was set at P <0.05 for all statistical tests. For
each test, degrees of freedom (df) and significance
levels are reported. All results are presented as mean ± standard error (SE).
All post hoc test results reported in compact letter display format in table as
well as in chart, where groups are represented by superscript alphabetical
letter. Groups with the same letter are statistically significantly similar and
the others are statistically significantly different. Those groups, which are
represented by more than one letter, are similar to groups represented by the
same letter.
Results
House Sparrows roost communally.
Often large numbers of sparrows aggregate at night shelter and form a
significant communal roost which can be easily identified from a distance by
pronounced roosting vocalization of the sparrows. In the current study, Ziziphus xylopyrus,
Ziziphus jujube, Prosopis Juliflora, Acasia
Senegal, and Bambusa vulgaris were
used as roosting plants by sparrows (Image 2). However, sparrows also used Punica granatum, Morus alba, Syzygium
cumini, Ficus
religiosa, and Banyan tree Ficus
benghalensis for roosting purposes, often in the
absence of the aforementioned roosting plant species (Table 1), sparrows often
used empty nests for roosting purposes, i.e., roost nest (Image 3E). During the
study, it was observed that roosting sparrows often visited or gathered at
pre-roosting sites (other than roosting sites) before entering a roosting
plant. Various maintenance activities such as sand baths, preening, rubbing
bills and fluffing were observed during pre-roosting at all the sites (Image
3B). Sometimes collective motion (murmuration) was
observed during aggregation of large numbers of sparrows at roosting sites
(Image 3A). Collective motion of sparrows was common at urban and suburban
sites, mainly when a large aggregation of sparrows occurred during the
post-breeding season.
No significant statistical difference was
found in mean peak arrival time of sparrows across urban, suburban and rural
roosting sites for both the years (Figure 1). Peak arrival time of sparrows at
different roosting sites was strongly correlated with sunset time, which was
statistically significant, rs (202)=
0.848, p <0.0001 (Figure 2). Similarly, there was a strong positive
correlation between peak arrival time and day length, which was also
statistically significant, rs (202)=
0.819, p <0.0001 (Figure 3). During the observation, the peak numbers of
House sparrows were recorded 0.5 h before sunset. House Sparrows arrived at
roost sites in different flock size ranging 3–40. In 2017, there was a
significant statistical difference in mean arrival duration across urban,
suburban and rural gradients (H(2)= 16.99, p <0.0001). The Bonferroni post
hoc test revealed that mean arrival duration at rural gradient was
statistically significantly lower than urban (p <0.0001) and suburban
gradient (p <0.05). There was no statistically significant difference in
mean arrival duration between suburban and urban gradient (p >0.05) (Figure
4). Similarly, in 2018, there was a significant statistical difference in mean
arrival duration across different gradient (H(2)= 7.05, p <0.05). The
Bonferroni post hoc test revealed that mean arrival duration at suburban
gradient was statistically significantly higher than urban gradient (p
<0.05). There was no significant statistical difference in mean arrival
duration between urban – rural gradients and rural – suburban gradients (Figure
4). Besides, arrival duration varied significantly across the different
seasons. Usually, maximum arrival duration was recorded during monsoon and
post-monsoon seasons in the current study. House Sparrows presumably spent more
time in foraging due to favourable feeding conditions during these seasons,
consequently frequent back and forth movements from foraging ground to roosting
sites increased arrival duration.
No significant statistical
difference was found in mean peak departure time across urban, suburban and
rural gradients for both the years (Figure 5). There was a strong positive
correlation found between peak departure time and sunrise time, which was statistically
significant, rs(202)= 0.977, p <0.0001
(Figure 6). No significant statistical difference was found in mean departure
duration across urban, suburban and rural gradients for both years (Figure 7).
The roosting sound started when
House sparrows entered into roosting sites and lasted up to the end of nautical
twilight. The roosting sound sometimes was interrupted by warning calls
resulting in a sudden silence for a fraction of a minute. However, the roosting
sound restarted immediately on reoccurrence of favorable
conditions. It was observed that unlike the arrival pattern of sparrows, within
30 mins after sunrise, almost the maximum number departed together. Mostly
departure occurred in the same direction from where flocks of House sparrows
had arrived at the roosting site. Vocalization in the morning generally started
during the nautical phase of sunrise and lasted up to approximately 10–15 min
after the start of civil twilight. Further, it was observed that the House
sparrow easily shares its roosting place with small passerine birds, these
individuals may be of the same or different genus, i.e., heterospecific
communal roosting.
Under certain circumstances, such
as removal of roosting plant species or trimming of corresponding species
locally, reduction in foliage density of roosting plants, presence of larger
avian species at roost sites, House sparrows often change their roosting sites
and opt for other suitable patches, generally found at a distance of 0.22 ± 0.03
km within the study sites. However, due to restricted availability of suitable
patches within urban and suburban gradients, the distance of secondary roosting
plants (0.26 ± 0.05 km and 0.21 ± 0.04 km) was relatively higher than in rural
gradient (0.17 ± 0.04 km) (Table 2).
Discussion
It was observed during the study that House
sparrows mostly prefer to roost in dense bushy vegetation rather than in a tree
with dense canopy. According to North (1968), tree height and the density of
the foliage, rather than species of the plant are principle criteria for the
selection of roosting sites. It was observed that often due to small
disturbances sparrows opted for other suitable patches of plants found within
the study sites for roosting purpose either temporarily or permanently.
However, with the recurrence of favourable conditions part of the population
returned to the primary roosting sites. Anderson (2006) opined that sparrows
often change roosting sites if sites have less density of foliage. Pre-roosting
gathering was also significant at all study sites. Under certain circumstances
such as disturbance due to predators at the roosting sites, pre-roosting sites
played an important role by providing temporarily better shelter to sparrows.
In addition, various maintenance activities such as sand baths, preening,
rubbing bills, and fluffing were significant during pre-roosting at all sites
(Image 3B). Simmons
(1964) considered preening as an essential and significant act performed by
birds to maintain
their feathers. For removing parasites,
birds often shake their body or fluff their feathers. In the current study, sparrows
were found to preen their feathers regularly and it was significant during
pre-roosting visits. Sand bath was also significant in the House sparrow
population at the study area. Many studies have explained the importance of
sand/dust bath by birds for removal of parasites, besides the sand bath is also
essential as excess amounts of oil that birds daily preen on to their feathers
to stay warm and fly is absorbed (Borchelt 1972).
This stresses the importance of such characteristic habitats (e.g., sandy
surface), where sparrows can efficiently perform various maintenance activities
required for a healthy, sustainable life.
It was observed that sparrows
arrived at their corresponding roosting sites 1–1.5 h before sunset. This was
very similar to Anderson’s (2006) observation, where he noted the arrival of
sparrows at the roosting site two hours before sunset. No statistical
significant difference was found in peak arrival times across different sites
of each gradient between 2017 and 2018. However, peak arrival time was strongly
correlated with sunset time, this indicated that the arrival of the House
sparrows at the roosting site is totally influenced by photoperiod. However,
presumably, various factors such as illumination (direct sun light), presence
of raptors, and other larger avian species at the roosting site might play an
important role in delaying arrival time at roosting sites. Variances in arrival
duration of sparrows at roosting sites across urban, suburban and rural
gradient could be explained as birds spent more time for last moment foraging.
Statistically significant larger arrival duration in urban and suburban
gradient was due to prevalence of restricted suitable patches across such
gradients, where birds could spend more time for foraging. In 2018, the amount
of suitable patches was significantly reduced at suburban sites such as V P
Society (SUB1) and Forest colony (SUB2). Sometimes attacks by raptors such as Shikra Accipiter
badius on sparrows during arrival at roosting
sites made a pause in the arrival and increased the arrival duration. The peak
departure time and departure duration of sparrows from roosting sites did not
vary significantly across urban,
suburban and rural gradients during the study period. In the evening, the
roosting vocalization of sparrows was distinct and significant at all sites
through which communal roosting sites of sparrows could be located from a distance.
However, sometimes on warning calls, the roosting sound was interrupted for a
fraction of time which began again on the return of favourable conditions. Daanje (1941) reported that House Sparrows have social
warning calls through which the whole colony quickly learns of the presence of
an enemy in the vicinity.
It was observed that the departure of sparrows from different roosting
sites started by sunrise; 0.5 h to 1 h after sunrise a maximum number of
sparrows departed from roosting sites. Departure duration recorded in the
current study was a bit longer than
recorded by North (1968). However, peak departure occurred within 30 min after
sunrise during the current study too. It was observed that unlike the arrival
pattern of sparrows, within 30 min after sunrise, almost the maximum number of
the population departed together. Mostly departure occurred in the same
direction from where the flocks of sparrows arrived at the roosting site. North
(1968) noted the beginning of vocalization of the sparrows about 30 min before
sunrise, and they usually departed from the roost within 30 min after sunrise.
These observations of North (1968) are
also supported by the current study where during the nautical phase of
sunrise vocalization started and lasted up to approximately 10–15 min after the
start of civil twilight.
Heterospecific communal roosting was witnessed
in the current study too, where House sparrows roosted with other small
passerine birds on the same roosting plant. Heterospecific
communal roosts of House sparrows with different avian species are reported
across the globe. House sparrows were found to share roosting sites with
European Starlings in Poland (Gorska 1975), with
Spanish Sparrows in Spain (Alonso 1986), with European Starlings and Eurasian
Tree Sparrows in North America (North 1968; Anderson 2006). In India, Rana
(1989) observed communal roosts of House sparrows with Jungle Babblers Turdoides striatus
and Common Mynas Acridotheres
tristis. The above mentioned study supports the
observation of the current study, where a communal roost of House Sparrows has
been observed with Large Grey Babbler Turdoides
malcolmi, however, a record of sharing roosting
sites with Common Myna Acridotheres
tristis was lacking in the current study. Mahabal & Bastawade (1985)
reported communal roosting of House sparrows near the communal roosting site of
the Black Kite (Milvus migrans govinda).
However, it was observed in the current study, that the presence of larger
avian species such as Alexandrine Parakeet Psittacula
eupatria forced House sparrows to roost on
other plant species. Further, the opportunistic presence of larger avian
species at the study site also influenced House Sparrows’ behavioral
patterns. Like, when Painted Stork Mycteria
leucocephala was present at roosting sites—for
collecting corresponding nest materials from the site—sparrows swiftly entered
the roosting plant, without murmuration and without
producing any roosting calls, thus indicating that larger avian species
negatively influence roosting House Sparrows.
Conclusion
During the study, peak arrival
and peak departure times of the House Sparrow did not vary significantly across
urban, suburban and rural gradients of Bhavnagar. While arrival duration was
significantly larger in urban and suburban gradients, such variation in the
arrival duration could be explained by multiple factors such as restricted
availability of suitable patches, lack of suitable foraging grounds near roost
sites, and the presence of raptor birds. In the present study, dense bushy
vegetation was found to be the most preferred habitat of the House sparrow for
roosting and pre roosting purposes across urban, suburban and rural gradients
of Bhavnagar. Besides providing better night
shelter, bushy vegetation forms an ideal habitat with reference to maintenance
activities of the House Sparrow such as sand baths. During the study it was
observed that bushy vegetation was significantly reduced across urban and
suburban sites which resulted in a drastic reduction of suitable habitat
patches for the House Sparrow. Hence, conservative initiatives should not be restricted to complement nesting
opportunities by providing artificial nest sites, but attention should also be
given to preserving suitable habitats required for the species.
Table 1. List of different plant
species used by House Sparrows for roosting during the study.
Roosting plant species |
||||
|
Scientific name |
Common name |
Family |
|
1 |
Ziziphus xylopyrus |
Moti boradi |
Rhamnaceae |
|
2 |
Ziziphus jujuba |
Boradi |
Rhamnaceae |
|
3 |
Prosopis Juliflora |
Gando baval |
Fabaceae |
|
4 |
Acasia Senegal |
Gorad baval |
Fabaceae |
|
5 |
Bambusa vulgaris |
Vans |
Poaceae |
|
6 |
Punica granatum |
Dadam |
Lythraceae |
|
7 |
Morus alba |
Shetur |
Moraceae |
|
8 |
Syzygium cumini |
Jambu |
Myrtaceae |
|
9 |
Ficus religiosa |
Peepal tree |
Moraceae |
|
10 |
Ficus benghalensis |
Banyan tree |
Moraceae |
|
For
figures & images - - click here
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