Breeding
biology of the Small Bee-eater Merops orientalis (Latham, 1801) in NagapattinamDistrict, Tamil Nadu, India
S. Asokan1, A. Mohamed SamsoorAli2 & R. Manikannan3
1Associate Professor & 3Ph.D. Research
Scholar, Department of Zoology & Division of Wildlife Biology, A.V.C.
College (Autonomous), Mannampandal, Mayiladuthurai, Tamil Nadu 609305, India
2 Senior
Research Fellow, Owl Research Project, Department of Zoology, Saraswathi Narayanan College (Autonomous), Perungudi, Madurai, Tamil Nadu 625022, India.
Email:1 beeasokan@yahoo.co.in; 2 amsamsoor@yahoo.co.in (corresponding author); 3 manikannanr@yahoo.co.in
Date
of publication (online): 26 April 2010
Date
of publication (print): 26 April 2010
ISSN
0974-7907 (online) | 0974-7893 (print)
Editor: Ignacy Kitowski
Manuscript details:
Ms
# o2273
Received
29 July 2009
Final
received 26 December 2009
Finally
accepted 05 February 2010
Citation: Asokan, S., A.M.S. Ali & R. Manikannan(2010). Breeding biology of the Small Bee-eater Merops orientalis (Latham, 1801) in NagapattinamDistrict, Tamil Nadu, India. Journal of Threatened Taxa 2(4): 797-804.
Copyright: © S. Asokan, A. Mohamed Samsoor Ali
& R. Maikannan 2010. Creative
Commons Attribution 3.0 Unported License. JoTT allows unrestricted use of this article in any medium
for non-profit purposes, reproduction and distribution by providing adequate
credit to the authors and the source of publication.
Author Details: Dr. S. Asokan is currently teaching students, undertaking and
supervising various research activities. He has produced seven PhD and 40 MPhilstudents in various field of Wildlife Biology and
Zoology. He has published more
than 35 research papers in leading national and international journals.
A. Mohamed Samsoor Ali obtained his MSc degree in
Wildlife Biology from AVC College, Mannampandal in
2003 and has been working on various fields of Ornithology since 2004.
R. Manikannan is working on diversity of wetland birds in Point Calimere Wildlife Sanctuary for a PhD degree.
Author Contribution: The field study was conducted by AMSA and RM under the
supervision of SA. AMSA analyzed data and wrote the manuscript and SA provided
necessary suggestions during manuscript preparation.
Acknowledgements: We thank the
Ministry of Environment and Forests (MoEF),
Government of India for the financial assistance (Project No.
14/14/2001/ERS/RE) to undertake field investigations. We wish to express our
sincere thanks to the HOD and other Staff members of Zoology and the Principal
and the Management of A.V.C. College (Autonomous), Mannampandalfor having rendered facilities and encouragement. Thanks are also due to the anonymous reviewers for their
very constructive comments.
Abstract:
The breeding biology of Small Bee-eater Merops orientalis was studied in NagapattinamDistrict of Mannampandal, Tamil Nadu, India between 2005 and 2006. A total of 34 nests were studied and the bee-eaters were
found to excavate long tunnels ranging in length from 79 to 125cm (104.9±123.48
cm) and ending in widened egg chambers. The mean diameter and circumference of the entrance hole opening was
8.94±1.03 cm and 26.9±3.55 cm respectively. They excavated nest holes at a mean height of 52.1±2.69 cm
from the bottom and 158.7±4.11 cm from the top of sandy river
banks. The clutch size
varied from 3 to 6 with a mean of 3.5±0.88 and clutches of three were very
common. The egg dimensions ranged
between 23.0 x 20.0 mm and 18.0 x 14.0 mm. The weight of the eggs varied between 2.0 and 5.0 g (3.3±0.65
g). The mean incubation period of the Small Bee-eater was 14.4±1.01 days and
both sexes took part in the incubation. The Small Bee-eater laid 56 eggs, of which 43 hatched (76.7%) and 36
flew out of the nest, making the fledging success 83.7%. The newly hatched nestlings were 3.16 g
in weight and reached a maximum of 23.16 g on day 24. A reduction in weight was noticed in the last few days and
20.75g was reached on day 27. The other body parts attained maximum
maturity from hatching to fledging.
Keywords:Eggs, hatching success, nest-site, nestling growth, Small Bee-eater
For figures, images & tables – click here
Introduction
Bee-eaters (Aves: Meropidae)
are a clade of 26 species with considerable diversity
in social and breeding behaviors. The Small Bee-eater Merops orientalis is the most variable species in the family in regard to
plumage color and can be subdivided into 6–8 geographically variable
races (Fry 1984). They are common
in open cultivated fields, nest on the face of perpendicular banks of ravines,
sandy river banks and sandy bunds, gently sloping bare
ground and around cultivated tracts (Sridhar & Karanth1993). Small Bee-eaters are aerial
insectivores and can be seen foraging frequently in agricultural fields. Over 95% of their prey comes from
various insect’s viz., beetles, bees, dragonflies, butterflies, bugs and
grasshoppers (Asokan 1998; Asokanet al. 2009b). The nest-site
selection, helpers at nest and breeding performance of bee-eaters are discussed widely (Fry 1972; White et al. 1978; Lessells & Krebs 1989; Wrege& Emlen 1991; Kristin 1994; Kossenko& Fry 1998; Burt 2002; Boland 2004; Heneberg& Simecek 2004; Yuan et al. 2006). Information on
the bee-eater in India includes studies on distribution, population and feeding
(Hutson 1947; Inglis 1949; Ara 1951; Roy 1968; Lott 1985; Abrol1994; Joshua et al. 1997; Asokan 1998; Nirmala 2000; Asokan et al. 2003).
However, the breeding biology of the bee-eater is less exposed excepting for
information on some aspects from certain parts of India (Neelakantan1948; Bannerjee 1992; Sridhar & Karanth 1993; Asokan 1995). In this paper we address some detailed
information on nesting season, nest-sites, clutch size, egg morphometry,
incubation and nestling growth patterns of the Small Bee-eater in Nagapattinam District, Tamil Nadu, India.
Materials and Methods
The study was conducted on the Cauvery River banks and
the adjacent areas of Mannampandal (18°18’N
& 79°50’E) in Nagapattinam District,
Tamil Nadu, India between 2005 and 2006. Agriculture is the major economy of
this area, contributing a high share of rice production in the state. Sugarcane, groundnut, green gram, black
gram, cotton, etc are other major crops cultivated in this area. The river Cauvery and its tributaries
are the major perennial water sources used for irrigation. The predominant wood plant species
found in the study area includes Cocos nucifera, Borassus flabellifer, Mangifera indica, Enterolobium saman, Tamarindus indicus, Ficus benghalensis, Acacia arabica, and Azadirachta indica. Important
shrub species are Prosopis juliflora, Jatropha glandulifera, Adhathoda vesica. Plantations
of Casuarina equisetifolia, Tectona grandis and Bambusa arundinacea are
also found in the study area. The north-east monsoon usually brings rain to the study area
during October-December (65% of the total rainfall in a year); the dry season
occurs between May and July.
During the breeding season, the study area was
thoroughly searched to detect nests. The tunnel depth, diameter and circumference of the entrance opening,
distance of the hole to the bank bottom and distance of the hole to the bank
top of each nest was measured by using a standard measuring tape and wooden
scale (Asokan 1995). The tunnel depth was measured after the completion of
breeding activities i.e. nest was broken at the end of the nesting period. A
tunnel was slowly and carefully dug from one direction of the nest-site, to
reach the egg chamber. After the
egg measurements were completed the egg chamber was closed with a dark steel
plate for future use i.e. nestling
measurements. The distance to the
nearest agricultural lands, groves, human habitations, perch sites and electric
lines were measured in meters with a marked rope.
The freshly laid eggs were numbered with a felt-tipped
pen, measured with Vernier calipers and weighed to
the nearest 0.5g with a spring balance and care was taken to avoid excessive
disturbance, which might have attracted predators. The shape index of the eggs
was computed using the formula (Prasanth et al. 1994)
Si = B*100/L, where Si = shape index, B = breadth and L = length of the egg in
centimeters. The incubation period
was determined from the first egg laid till the first egg hatched.
The hatching success and fledgling success of the Small
Bee-eater were calculated by using the following formulae:
Hatching
success (%) = (No. of eggs hatched / total no. of eggs laid) x 100
Fledging
success (%) = (No. of nestlings fledged / total no. of nestlings hatched) x 100
Growth changes in the Small Bee-eater nestlings were
measured from hatching to fledging and the method of Pettingil(1985) was employed for measuring nestlings. All the nests were visited every 3 days for taking morphometric measurements of the body parts. Disturbances were
minimized by handling the nestlings very carefully during the measurements. All the nestlings were allotted
individual identification marks. Totally eight measurements were made (i) body
weight, using a spring balance of 1g accuracy; (ii) body length, from the tip
of the bill to the tip of the longest rectrix; (iii)
bill length, from the tip of the upper mandible to the base of the culmen; (iv) bill depth, distance between the upper and
lower mandible; (v) wing length, as the straight length from the bend of the
wing to the tip of the longest primary; (vi) wing span, the distance from tip
to tip of the longest primaries of the outstretched wings; (vii) tarsus length,
measurement from the base of the tarsometatarsus to
the base of the middle toe and (viii) tail length, the distance from the tip of
the longest rectrix to the base of the middle rectrices.
Descriptive statistics are mean followed by standard
deviation (SD). The Pearson simple
correlation equation was used to test any relationship between egg weight and
egg shape index. The significance
of the test was assessed at p = 0.05. The MINITAB 13.1 statistical package was used for all the analyses. The
results of the above analyses were interpreted using standard statistical procedures
(Sokal & Rohlf 1981).
Results
Nesting season
The nesting season of the Small Bee-eater was initiated
in March and ended in June. Breeding was quite synchronous among the local populations of the Small
Bee-eaters. Excavation of the nest
cavities was in its final stages or complete by mid-March.
Nest and nest-sites
Totally 34 nests of the Small Bee-eater were recorded
during the study period. Of these
15 nests were active and 19 were inactive. The inactive or old nests were
identified by a typical hole pattern and undigested
insect remains found in the nest hole and egg chamber. Nest burrows were located along the
sides of river banks (95%) and sandy grounds (5%) (Image 1). Nests consisted of tunnels that measured 8.9±1.03cm in diameter (range
7.2-11.2cm) and 26.9±3.55 cm in circumference (range 18-36cm). The entrance
tunnels were angled and it was impossible to see into the nesting cavity from
outside the entrance. The posterior end of the tunnel was wide and formed the
nesting chamber. The length of the nest tunnels varied from 79 to 125cm with a
mean length of 104.9±13.48 cm (Table 1). The small Bee-eater excavated the nests at a mean
height of 52.1±2.69 cm from bottom and 158.7±4.11 cm from top of the river banks. Distance to agricultural lands (13.2±2.87 m), perching sites (0.5±0.33
m) and electric lines (13.6±2.17 m) were closer to the nest-sites (Table 1).
Eggs and clutch size
The eggs of the Small Bee-eater are
spherical and small in size (Image 2). In total 56 eggs were examined during the study. Longer and thinner eggs had lower shape
index while shorter and thicker ones had higher index. No correlation could be found between
weight and shape index (r = -0.067, p = 0.1371, df =
56). The eggs are white in color
with no markings or spots. The
highest weight of eggs examined during the study was 5g and lowest 2g and the
average 3.3±0.65 g. The minimum
length of the egg was 20mm and minimum width 14mm. The maximum egg length was 23mm and width 18mm. The mean length was 21±0.09 mm and the
width 14±0.11 mm (Table 2). The
clutch size varied from 3 to 6 with a mean of 3.7±0.88. Clutches of three and
four were most common and had a percentage frequency of 46.6 and 40.0
respectively. Clutches of five and
six were very rare (Fig. 1). The
56 eggs examined during the present study belonged to 15 clutches.
Incubation
Incubation started after laying the first egg. The incubation period of 41 eggs
observed in the present study, ranged from 14-16 days. The mean incubation period was 14.4±1.01
days. Both the parents were
observed to incubate the eggs. While one bird sat on the eggs, the other remained very close to the
nest perched on small shrubs within reach, watching over the nest.
Hatching and fledging success
Out of 56 eggs examined for the purpose, 43 hatched;
hatching success was 76.7%. Of the remaining eggs, four eggs were broken and
nine remained unhatched. From the 43 hatched eggs, 36
nestlings were successfully flown out the nest and making the fledging success
of 83.7%.
Plumage development
The freshly hatched nestlings were naked, with fleshy
pink skin and closed eyes. The
nestling had a bulging abdomen that was almost transparent. The bill was light black, slightly
brighter yellow near the tip of the lower mandible. Six days later the skin turned pinker and the eyes began to
partially open. Nestlings appeared
‘spiky’, with many pins now just out above the skin surface. Caudal tract was just visible as a few
gray flecks. On day ten, contour
feathers in the capital and dorsal areas began breaking their sheaths, slaty grey. Eyes were typically beginning to open. Bill was darkening with a gray tip and the nestling was able
to produce soft clicking noises. On day 15, primaries and secondaries showed
light tips. Several femoral and crural pins had
emerged. Contour feathers were
well broken from their sheaths, slaty in the dorsal,
capital and throat regions. The
caudal tract was well developed. At 20 days the nestlings’ unsheathed green feathers were well developed
throughout the body and the tips of the wing coverts appeared black coloured. The nestlings were very active, standing and
jumping and produced typical calls. On day 25, the nestlings resembled adults. The body was fully covered with green feathers, head and neck
were tinged with reddish-brown and the bill and legs were black.
Nestling growth patterns
In the Small Bee-eater, hatching was asynchronous.
Nestlings grew from 3.16±0.28 g (N=43) at hatching to peak weight of 23.16±2.10
g (N=25) at day 24, then slowly declined and reached a weight of 20.75±0.57 g
(N=16) on day 27 (Fig. 2). The
body length of nestlings grew from 3.73±0.21 cm at hatching to 15.93±0.04 cm by
the end of day 27. The bill length
was 0.11±0.03 cm at hatching and it grew to 2.52±0.01 cm on day 27. The bill
depth of the nestling was 0.11±0.03 cm at hatching and finally attained a size
of 0.88±0.01 cm. At the time of hatching, the length of the wing was 1.39±0.11
cm and it gradually increased and attained a maximum length of 10.57±0.05 cm on
day 27. The tarsus length of the
nestlings grew from 0.26±0.06 cm at hatching to 2.63±0.01cm by the end of day
27. The tail length showed a
considerable amount of growth during the nestling period. The growth was 0.14±0.05 cm at hatching
and it increased to 4.17±0.04 cm by day 27 (Fig. 2).
Discussion
The Small Bee-eater breeds from
March to June depending on the food availability. Earlier, Asokan (1995) studied the breeding biology of the Small
Bee-eater in the study area; he reported that it actively breeds during April
to June. Sridhar & Karanth (1993) stated that the nesting season of the Small
Bee-eater around Bangalore was February-August, with peak breeding around
April-May. Various factors viz.,
temperature, rainfall, suitable nesting sites, food availability and helpers in
the nest influenced the breeding season of the bee-eater.
In the present study 95% of the nests were recorded in
the sandy river banks. Earlier studies have also reported that bee-eaters, in
general, preferred sandy river banks for nest
construction (Sridhar & Karanth 1993; Kristin
1994; Asokan 1995; Burt 2002; Heneberg& Simecek 2004; Schmidt & Branch 2005; Yuan
et al. 2006). Sandy soil
preference for nesting were also reported of other soil excavating nest speciesviz., White-breasted Kingfisher Halcyon smyrnensis (Madhuramozhi 2008), Eurasian
Kingfisher Alcedo atthis (Heneberg 2004), Belted
Kingfisher Ceryle alcyon (Brooks & Davis 1987) and Sand Martin or Bank
Swallow Riparia riparia (John 1991; Heneberg2003). Sandy soils have lower soil
pressure, density and moisture than more clay-rich soils. Sandy soils probably provided faster
and easier excavation of nest cavities. With high porosity, nest tunnels constructed in sandy soils would also
have better ventilation, which is important to diffuse gases to maintain a
tolerable level of O2 and CO2 in the nest cavities (White
et al. 1978). Soil particle size
could also affect the structure of the nest tunnels of the Small Bee-eater.
The Small Bee-eater excavated a tunnel from 79 to 125cm
with a mean depth of 104.9cm. Ali
& Ripley (1983) and Fry & Fry (1992) reported that the Small Bee-eater
builds a one or two meter horizontal tunnel along river banksand sandy grounds. The nest
entrance had a mean diameter of 8.9±1.03 cm while the circumference of the nest
was 26.9±3.55 cm. These
measurements are more or less similar to those reported by Ali & Ripley
(1983) and Asokan (1995). It builds a tunnel 52.1cm above the ground and 158.7cm from
the top of the river banks. Cornwell (1963) reported that the Belted Kingfisher
constructed a nest at least five feet above the ground and 12 to 18 inches from
the top of the embankment, near the bottom of the organic soil layer. The agricultural lands, perch sites and
electric lines were closer to the nest-sites. The agricultural lands provided a variety of protein rich
insect prey to the parents as well as to the nestlings. The nearest small trees, shrubs, sticks
and electric lines served as a perching site for overseeing the nest and
searching for prey (Asokan et al. 2008, 2009a). In this study, we found that the Small
Bee-eater avoided placing nest cavities in areas with dense vegetation. Many bee-eater species have also been
seen nesting on river banks without much vegetation
(White et al. 1978; Kossenko & Fry 1998; Boland
2004; Yuan et al. 2006). Predation
is a constant threat to successful reproduction in this species and reduced
vegetation at the nesting sites probably facilitates detection by predators and
increases the effectiveness of mobbing behavior.
The Small Bee-eater was found to lay small eggs with a
mean length and width of 21.0±0.09 mm and 14.0±0.11 mm and weighing 3.3±0.65
g. Asokan(1995) reported that egg measurements for the Small Bee-eater i.e., mean
length, width and weight were 21.0mm, 18.0mm and 2.62g. Egg measurements in the present study
are in full agreement with those of the previous report. Clutch sizes varying from 4 to 7 (Ali
& Ripley 1983) and 2 to 5 per clutch (Asokan1995) were reported. In the
present study, clutch size of the Small Bee-eater varied from 3 to 6 and the
majority (46.6%) was three. Similar clutch sizes have also been reported in different bee-eater
species viz., 1-4 in Black-headed Bee-eater Merops breweri (Schmidt & Branch 2005), 2-5 in White-fronted
Bee-eater M. bullockoides (Wrege& Emlen 1991) and 2-6 in European Bee-eater M. apiaster (Hoi et al. 2002). Several factors might contribute to clutch size variability viz.,the condition of the breeding
female, availability of resources necessary to produce eggs, presence of
helpers at the nest, time of laying in the season and anticipated future
availability of food for feeding nestlings (Klomp1970; O’Connor 1984; Lessels & Krebs 1989; Asokan 1995). Wrege & Emlen (1991) recorded
that insect availability and rainfall over the 3-month period before laying accounted for 16% of variations in clutch size of the
White-fronted Bee-eater.
The mean overall hatching success as recorded in the
present study was 76.7%. Earlier, Asokan (1995) recorded a similar hatching success (78.81%)
in Small Bee-eater populations in the Mayiladuthuraiarea. During the present study the incubation and hatching sequence was found
to be asynchronous. The majority of altricial bird
species hatch their young asynchronously because incubation begins before the
clutch is complete and eggs, therefore, hatch over a period of one or more days
in approximately the order in which they were laid. Wrege & Emlen(1991) and Asokan (1995) have recorded asynchronous
hatching patterns in bee-eater species. This enhances the ability of older nestlings to monopolize limited food
supplies and results in selective death of the smallest nestlings first. Such brood reduction coupled with the
ability of nestlings to slow their development rate in response to food stress,
is considered an adaptation for coping with the unpredictable variations in
food supplies commonly met by these birds.
In the present study the overall mean fledging success
of Small Bee-eater was 83.7%. These values are relatively more than those reported for the
White-fronted Bee-eater (41%) by Wrege & Emlen (1991) and the Small Bee-eater (79.13%) by Asokan (1995). This shows that lower clutch size for the Small Bee-eater in the present
study was compensated by relatively high fledging success, thereby ensuring
overall reproductive success of this species. Lessels & Krebs (1989)
reported that among European Bee-eater fledglings, as or nearly as,
asynchronous as hatching, the last chick to leave fledges about 32 days after
the first chick hatches and 28 days after the last, at an age independent of
hatching asynchrony. In the case
of Small Bee-eater fledging was found to occur in 26-28 days. Lessels &
Krebs (1989) reported that Bee-eaters continue to feed their young even after
fledging because the capture of fast flying insects is a skill
which may require time to acquire and as such Bee-eater chicks
presumably continue to be dependent on their parents for sometime after
fledging.
The weight of chicks on the first day was 3.16g which increased to 23.16g at 24 days of age. However, there was a drop in the mean
weight of nestlings in last few days and reached 20.75g at the time of
fledging. Many observers have noted a decrease in rate-of-gain in weight as
feathers were being produced or as temperature control was being
established. Banks (1959) reported
that the decrease in actual and relative gain in weight in the final three days
of nestling life in the White-crowned Sparrow Zonotrichia leucophrys was probably due to a shift in the energy budget, as
more food was utilized in production of feathers and heat. Welty (1982) stated that many nestlings
lost body weight a few days before leaving the nest. This loss was supposed to be due to the utilization of fat
deposits and skeletal muscles for the energy to leave the nest. This body weight reduction is
advantageous for moving out of the nest. Krebs & Avery (1984), Lessels & Ovenden (1989), and Emlen et al.
(1991) recorded significant weight loss before fledging in the nestlings of Merops species. This loss of weight is found in some aerial insectivores like swallows,
martins and swifts (Ricklefs 1968; Languy & Vansteenwegen 1989)
and other bird species (Kumar & Rao 1984;
Haggerty 1994; McCarty 2001; Nagarajan et al. 2002; Penteriani et al. 2005; Greeny2008; Asokan et al. 2009a).
The development of the different structure of the
nestlings was not uniform throughout the nestling period. The body length, bill
length, wing length, wing span, tail length and tarsus
length attained the maximum maturity at the time of fledging stage. The Small Bee-eater used above body
parts immediately after fledging for successful survival. This growth allometryin the adaptive parts had been observed in several avian species (Pinkowski 1975; Best 1977; Olsen et al. 1982; Zach & Mayoh 1982; Kumar 1983: Teather1996; Aparicio 2001; Pereyra& Morton 2001; Asokan et al. 2009a).
Variability in nestling growth rates might be due to
many ecological factors. Ecological factors that influence the nestling growth of Small
Bee-eaters are generally related to limitations in food availability, weather,
habitat differences and quality, parasites, competition between nest mates and
parental abilities.
References
Abrol, D.P.
(1994). Seasonal activity, population dynamics and behaviour
of Bee-eater birds (Coraciiformes: Meropidae) attacking honeybees. Pavo 32:
153-159.
Ali, S. & S.D. Ripley (1983). Handbook of Birds of India and Pakistan. Oxford
University Press, Bombay.
Aparicio,
J.M. (2001). Patterns of growth and fluctuating
asymmetry: the effects of asymmetrical investment in traits with determinate
growth. Behavioural Ecology and Sociobiology49: 273-282.
Ara, J. (1951). Distribution of the Bluebearded Bee-eater
(Alcemerops athertoni).Journal of the Bombay Natural History Society 50(1): 175-176.
Asokan, S. (1995). Ecology of the Small Green Bee-eater,Merops orientalisLatham 1801 with special reference to its population, feeding and breeding in Mayiladuthurai, Tamil Nadu, South India. PhD.
Thesis, Bharathidasan University, Thiruchirappalli,
India.
Asokan, S. (1998). Food and feeding habits of the Small
Green Bee-eater Merops orientalisin Mayiladuthurai. Journal of Ecobiology 10(3): 199-204.
Asokan,
S, A.M.S. Ali & R. Manikannan (2008). Foraging ecology of the Black Drongo Dicrurus macrocercus (Vieillot) in an agro-environment,Nagapattinam District, Tamil Nadu. Indian Journal of Ecology 35(2): 170-172.
Asokan,
S, A.M.S. Ali & R. Manikannan (2009a). Nest-site selection and nestling
growth patterns of the Common Myna, Acridotheres tristis (Linnaeus, 1766). Geobios 36: 65-70.
Asokan, S, A.M.S. Ali & R. Manikannan(2009b). Diet
of three insectivorous birds in NagapattinamDistrict, Tamil Nadu, India – a preliminary study. Journal of Threatened Taxa 1(6): 327-330.
Asokan, S., K. Thiyagesan & R. Nagarajan (2003). Studies on Merops orientalisLatham 1801 with special reference to its population in Mayiladuthurai,
Tamil Nadu. Journal of Environmental Biology 24(4):
477-482.
Banks, R.C.
(1959). Development of
nestling White-crowned Sparrows in central coastal California. Condor 61: 96-109.
Bannerjee, A.K.
(1992). Some observations on the breeding behaviour of Bluebearded Bee-eater and Indian Small Green Bee-eater. Zoos’ Print 7(12): 19-21.
Best, L. (1977). Nestling biology
of the Field Sparrow. Auk 94: 308-319.
Boland, C.R.J.
(2004). Breeding biology of Rainbow
Bee-eaters (Merops ornatus): a migratory, colonial, cooperative bird. Auk 121:811–823.
Brooks, R.P. & W.J. Davis (1987). Habitat selection by breeding Belted
Kingfishers (Ceryle alcyon). American Midland Naturalist 117: 63-70.
Burt, D.B.
(2002). Social and
breeding biology of Bee-eaters in Thailand. Wilson Bulletin 114(2): 275-279.
Cornwell, G.
(1963). Observations on
the breeding biology and behavior of a nesting population of Belted
Kingfishers. Condor 65: 426-431.
Emlen,
S.T., P.H. Wrege, N.J. Demong& R.E. Henger (1991). Flexible growth rates in nestling White-fronted
Bee-eaters: a possible adaptation to short-term food shortage. Condor 93: 591-597.
Fry, C.H.
(1972). The social
organization of bee-eaters (Meropidae) and
co-operative breeding in hot climate birds. Ibis114: 1-14.
Fry, C.H.
(1984). The bee-eaters. T & A.D. Poyser, London, United
Kingdom.
Fry, C.H. & K. Fry (1992). Kingfishers, Bee-eaters and Rollers: A Hand Book. Christopher Helm. A and C Black, London.
Greeny,
H.F. (2008). Nestling growth and plumage
development of the Spotted Barbtail (Premnoplex brunnescens). Kempffiana 4: 21-29.
Haggerty,
T.M. (1994). Nestling growth
and development in Bachman’s Sparrows. Journal of Field Ornithology 65:224-231.
Heneberg,
P. (2003). Soil particle composition affects
the physical characteristics of Sand Martin Riparia riparia holes. Ibis 145:
392-399.
Heneberg,
P. (2004). Soil particle composition of
Eurasian kingfishers’ (Alcedo atthis) nest sites. Acta Zoologica Academiae Scientiarum Hungaricae 50: 185-193.
Heneberg, P. & K. Simecek(2004). Nesting European
bee-eaters (Merops apiaster) in Central Europe depends on the soil characteristics
of nest sites. Biologia 59: 205-211.
Hoi, H., C.
Hoi, K. Kristofik & A. Darolova(2002). Reproductive success decreases
with colony size in the European bee-eater. Ethology Ecology & Evolution 14: 99-110.
Hutson,
H.P.W. (1947). On the migrants of Merops apiaster Linnaeus and Merops superciliosus Linnaeus in the Middle East and India. Ibis89(2):
291-300.
Inglis,
C.M. (1949). The BluebeardedBee-eater (Alcemerops athertoni) on the Nilgiris. Journal of the Bombay Natural History Society 48: 581-582.
John, R.D.
(1991). Observations on
soil requirements for nesting Bank Swallows, Riparia riparia. Canadian Field Naturalist 105: 251-254.
Joshua, J.,
V. Gokula & P. Sampathkumar(1997). Rare sighting and range extension
of European Bee-eater (Merops apiaster). Newsletter for Birdwatchers37: 15.
Klomp,
J.R. (1970). The
determination of clutch size in birds – review. Ardea58(1): 1-124.
Kossenko, S.M. & C.H. Fry (1998). Competition and coexistence of the
European Bee-eater Merops apiasterand the Blue-cheeked Bee-eater Merops persicus in Asia. Ibis 140: 2-13.
Krebs, J.R. & M.I. Avery (1984). Chick growth and prey quality in the
European Bee-eater (Merops apiaster). Oecologia (Berlin) 64:
363-368.
Kristin, A.
(1994). Breeding biology and diet of the
bee-eater (Merops apiaster) in Slovakia. Biologia Bratislava49: 273-279.
Kumar, T.S.
(1983). Bill
growth in the Spotted Owlet Athene brama brama (T). Raptor Research Centre Publications 2: 1-4.
Kumar, T.S. & J.V.R. Rao (1984). Some observation on the weights of
nestling Spotted Owlet Athene brama brama(T) prior to flying. Geobios 11: 229-231.
Languy, M. & C. Vansteenwegen(1989). Influence of parental age on the growth of nestling Swallows (Hirundo rustica). Ardea 77(2): 227-232.
Lessels, C.M. & G.N. Ovenden(1989). Heritability of wing length in European Bee-eaters (Merops apiaster). Condor 91: 210-214.
Lessels, C.M. & J.R. Krebs (1989). Age and breeding performance of
European Bee-eater. Auk 106: 375-383.
Lott, E.J.
(1985). European Bee-eaters (Merops apiaster) in Karnataka. Journal of the Bombay Natural History Society 82:
411.
Madhuramozhi, G. (2008).Ecology of the White-breasted Kingfisher, Halcyon smyrnensis (Linnaeus 1758) with special reference to its
population, foraging and breeding in Nagapattinam,
Tamil Nadu, India. PhD. Thesis, BharathidasanUniversity, Thiruchirappalli, India.
McCarty,
J.P. (2001). Variation in
growth of nestling Tree Swallows across multiple temporal and spatial scales. Auk 118: 176-190.
Nagarajan, R., K. Thiyagesan, R. Natarajan & R. Kanakasabai (2002). Patterns of growth in nestling Barn-owls.Condor 104: 885-890.
Neelakantan, K.K.
(1948). On the breeding of the Blue-tailed Bee-eater (Merops superciliosus)
in Rajahmundri, East Godavari district. Journal
of the Bombay Natural History Society 47: 741-742.
Nirmala,
T. (2000). Foraging
and feeding the fledgling of the BluebeardedBee-eater. Newsletter for Birdwatchers 40(4): 55.
O’Connor,
R.J. (1984). The growth and development of birds.Wiley and Sons, New York.
Olsen, P.D., J. Olsen, & N.J. Mooney (1982). Growth and development of Brown
Goshawks (Accipiter fasciatus), with details of breeding biology. Emu 82: 189-194.
Penteriani, V., M.M. Delgado, C. Maggio, A. Aradis & F. Sergio
(2005). Development of chicks and predispersal behaviour of young in the Eagle Owl (Bubo bubo). Ibis 147: 155-168.
Pereyra, M.E. & M.L. Morton (2001). Nestling growth and thermoregulatory
development in subalpine Dusky Flycatchers. Auk 118:
116-136.
Pettingill, O.S. Jr. (1985). Ornithology in Laboratory and Field. Academic Press, London.
Pinkowski, B.C. (1975). Growth and development of Eastern Bluebirds. Bird Banding 46: 273-289.
Prasanth,
J.J., V.V. Rao & V. Nagulu(1994). Nesting, egg size, incubation and
factors affecting clutch size in Little Egret, Egretta garzetta at Nellore Andhra Pradesh. Pavo 32(1&2):
67-72.
Ricklefs,
R.E. (1968). Patterns of
growth in birds. Ibis 110: 419-451.
Roy, M.B.
(1968). Occurrence of
the European Bee-eater Merops apiaster Linnaeus, at Mettur Dam, Salem district, Madras. Journal of the Bombay Natural History Society 65: 776.
Schmidt, B.K. & W.R. Branch (2005). Nests and eggs of the Black-headed
Bee-eater (Merops breweri)
in Gabon, with notes on other bee-eaters. Ostrich76(1&2): 80-81.
Sokal, R.R. & F.J. Rohlf(1981). Biometry. W.H. Freeman and Company, New York.
Sridhar, S. & K.P. Karanth (1993). Helpers in cooperatively breeding
Small Green Bee-eaters (Merops orientalis). Current Science 65: 489-490.
Teather,
K. (1996). Patterns of
growth and asymmetry in nestling Tree Swallows. Journal of Avian Biology 27: 302-310.
Welty, C.J.
(1982). The life of birds. W.B.
Saunders Company, London.
White, F.N.,
G.A. Bartholomew & J.L. Kinney (1978). Physiological and ecological correlates of tunnel nesting in
the European Bee-eater, Merops apiaster. Physiological Zoology 51: 140-154.
Wrege, P.H. & S.T. Emlen(1991). Reproductive success in Bee-eaters. Auk 108: 673-687.
Yuan, H.,
D.B. Burt, L. Wang, W. Chang, M. Wang, C. Chiou &
T. Ding (2006). Colony site
choice of blue-tailed bee-eaters: influences of soil, vegetation and water
quality. Journal of Natural History 40(7-8): 485-493.
Zach,
R. & K.R. Mayoh (1982). Weight and feather growth of nestling
Tree Swallows. Canadian Journal of Zoology60: 1080-1090.