Vol.2, No.4, 178-182 (2012)
http://dx.doi.org/10.4236/oje.2012.24021

Open Journal of Ecology

The nestling diet of fairy pitta Pitta nympha on Jeju
Island, Korea
Eun-Mi Kim1, Chan-Ryul Park1,2*, Chang-Wan Kang3, Se-Jae Kim4
1

Warm-temperate Forest Research Center, Korea Forest Research Institute, Seogwipo, Korea
Division of Forest Ecology, Korea Forest Research Institute, Seoul, Korea; *Corresponding Author: park@forest.go.kr
3
The Korea Association for Bird Protection Jeju Branch, Seogwipo, Korea
4
Department of Biology, Jeju National University, Jeju, Korea
2

Received 1 July 2012; revised 4 August 2012; accepted 29 August 2012

ABSTRACTThe nestling diet of the Fairy Pitta (Pitta nympha)
was studied by videotaping during breeding period in Jeju Island, 2009. Earthworms of several
species were the most common food resources
for nestlings, averaging 82% of all items, followed by 4% of Homoptera larvae. The remaining was only rarely recorded, including Lepidopteran larvae and adults, slugs, spiders, beetle adults and larvae (Coleoptera) and grasshoppers. Adults provided the number of preys
ranging from 1 to 7 items to chicks per one visit.
The average value of prey number per visit was
3.0 (SD = 1.38). The estimated average length of
prey was 5.7 cm (SD = 2.85), and 96% of the fooditems were smaller than 10 cm. The staying timefor feeding in an early stage was longer thanother stages. Provision rate at a forenoon (mean± SD, 14.7 ± 4.92) and an afternoon time (15.8 ±5.30) was not significantly higher than that ofnoon time (11.7 ± 4.49). These results provide
basic information for conservation action of international endangered species of this species.
Keywords: Earthworm; Prey Availability; Prey Size;
Rainfalls; Videotaping

1. INTRODUCTION
The Fairy Pitta (Pitta nympha) is migratory, breeds inforest habitats of Taiwan, Japan, southeastern China, andKorea and winter mainly on the Borneo [1]. Its population is suspected to be rapidly declining owing to deforestation in its breeding ranges, principally for agriculture
and timber, locally compounded by trapping for the cage
bird trade. It is listed as being in a vulnerable C1 statusaccording to IUCN (International Union for Conservation of Nature) criteria [2]. The birds are highly susceptible and inhabit a dark, humid, and dense forest which is
Copyright © 2012 SciRes.

difficult for person to approach. A detection of the Fairy
Pitta is difficult, then we don’t understand its lifestyleand ecology. For conservation of this threatened species,
ecological studies on its breeding habitat requirements
are essential [2]. In Korea, Fairy Pitta was recorded at
Geoje Island, Bogil Island and Daejeon, Jeju Island andmost brood in Jeju Island located at the southern part ofcountry. It arrived in late May for breeding and adults
engage in singing. Adults lay the 1st eggs in early June.
The clutch size ranges from 3 to 6, but 3 or 6 are rare.
Most young birds are observed from late June to earlyAugust. This species was mainly found around large andsmall valley and evergreen forests [3]. Only we had few
survey records on this bird conducted at the avifauna
research in Korea. Before 1945, a few Japanese scholars
recorded its observation at the southern slope of Mt.Hallabased on the collection and the song near the Gwaneumsa temple. At 1950s, we had only one record in thebook which American Austin had recorded about Jejulived 5 birds. In 1960s, Korean scholars started the study
about Fairy Pitta and recorded that the bird inhabitedfrom 1200 m to 1600 m above sea level around Youngsilgiam ridge [4]. Reference [5] reported that this species
brood around 1000 to 1200 m in the altitude. In 1980s,
some local scholars reported that it was observed at a
Suak and a Donnaeko valley, ranging from 500 m to 600 m
in northern part of Mt.Halla. Reference [6] reported that
this species distributed from 100 m to 800 m and themain distribution area from 400 m to 500 m at Jeju Island, Korea. The breeding success of this bird probably
depends on the availability of suitable nestling habitat
provide adequate prey for nestlings [7]. In this study, we
collected quantitative data on the nestling diet of the
Fairy Pitta.

2. STUDY AREA AND METHODS
2.1. Study Area
This study was conducted at Jeju Experimental Forests(JEFs), Seogwipo city in southern slope of Mt.Halla, Jeju
OPEN ACCESSE.-M. Kim et al. / Open Journal of Ecology 2 (2012) 178-182

Island, Korea (126˚39'E, 33˚21'N) from June to July,
2009. This area is about 1191 ha with elevations ranging
from 300 to 750 m, and certificated forest for forest
management by FSC (Forest Stewardship Council). Climate is subtropics, warm-temperate and temperate zone.
Annual precipitation is about 3000 mm. Major forest types
are evergreen forests, such as Quercus acuta, Castanopsis sieboldii, Neolitsea aciculata and N. sericea anddeciduous forests such as Carpinus laxiflora, Quercus
serrata and Styrax japonica. Others are Cedar plantation
forests. Soil depth is relatively deep and has developed
well in organic layer and stratum [8].

2.2. Video Recording
In study area, the Fairy Pitta arrived in late May andbegan actively singing. Most nests were built on the bigrock at a steep slope, with staking the forks of trees like a
big rugby ball. We selected two nests and recorded nesting activities with a video recorder (SONY HCR-H1)
and saved the files at the digital video recorder (ARGUS
Network DVR XAD-401). We set up the instrument andrecorded images during two months with an unmanned
video device to minimize the potential disturbance and to
avoid the breeding parents of Fairy Pitta abandoning thenests. The equipment operates during night and day tocatch what parents to do, when to start and finish feedingin night. We did not touch the nest, any juveniles andparents during recording periods. Also, we did not identify the any predator attacking nests. So, we did not affect any breeding process in getting the breeding imagesby setup the video instruments.

2.3. Video Analysis
We summed the data of two nests and analyzed thenumber of visit by parents, and number of prey per one
visit, and the prey size at the 2 cm intervals (2, 4, 6, 8, 10,
over 10 cm) according to the bill size of parents. Billsizes were obtained by previous results [3]. We analyzed
the life stage of prey as larval or adult and classified theprey type into earthworms, Homoptera, Lepidoptera,
Coleoptera, Orthoptera, slugs and spiders. The length ofthe prey was determined by at the interval of 2 cm comparing with the length of parents’ bill.

179

among times [10].

3. RESULTS
3.1. Diet Composition
Four nestlings departed the nest successfully at two
nests respectively. The nestlings left their nests on the
13th day after hatching at two nests. In total, 372 feeding
visits were recorded during the study period. Parents offairy pitta visited 274 times with prey items, and we
identified and recorded the contents of 826 prey items.
Earthworms of several species were the most common
prey items for nestlings, averaging 81.7% of all preys.
Homopteran larvae were the second largest identifiablefood item, comprising 4% of prey items. The others were
only rarely recorded, including Lepidopteran larvae andadults, slugs, spiders, beetle adults and larvae (Coleoptera) and grasshoppers (Orthoptera, Figure 1).

3.2. Number of Prey Items per Visit
Parents brought the number of prey ranging from 1 to
7 items per visit, but they delivered the prey at the average number of 3.0 ± 1.38 (n = 274) items per one visit.
Visit numbers ranging from 2 to 4 composed of 67% of
the feeding visit (Figure 2(a)). Number of delivered
preys was affected by food types, there was a significant
difference of percentage distribution of number of delivered preys between earthworms (3.0 ± 1.33; n = 224) andthe others (1.4 ± 0.64, n = 111, Mann-Whitney U test, Z= –10.415, p < 0.001, Figure 2(b)). Parents delivered
diverse numbers of earthworms to the nestlings, but they
did no more than three preys of the others.

3.3. Number of Prey Items per Visit
Average length of delivered prey was 5.7 ± 2.85 cm (n= 826), and 96% of the food items were smaller than 10 cm

2.4. Statistical Analysis
Parents transferred prey from 500 to 2000 hrs, so we
divided total timed into three times like forenoon (500 1000), noon (1000 - 1600), and afternoon (1600 - 2000)
due to the light intensity difference among three times indense forests. Fairy pitta do search prey at the forest floor,
so the light condition will affect the prey detectability.
We applied the Mann-Whitney U-test [9] with R statistic
program to understand the difference of number of prey
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Figure 1. Diet composition of the delivered prey based on
individual percentage by parents of fairy pitta.
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Average number ofdelivered preys

E.-M. Kim et al. / Open Journal of Ecology 2 (2012) 178-182

5
4
3
2
1
0

Earthworms

The others

70.0
60.0
50.0
40.0
30.0
20.0
10.0
0.0

Earthworms
The others
Total
1

2 3 4 5
6 7
Number of delivered preys

Figure 2. Average number (a) and percentage distribution (b) of delivered preys ofearthworms (n = 224) and the others (n = 111), and percentage distribution (b) of total delivered preys (n = 274).

(Figure 3(a)), but a few large items were observed. The
average length of earthworms (6.8 ± 2.39 cm, n = 670)
was significantly longer than the others (2.2 ± 1.11 cm,
Mann-Whitney U test, Z = –17.929, p < 0.001, Figure3(b)). The longest prey of earthworm was estimated at 13
cm in length. Earthworms only dominated the prey size
longer than 10 cm. So, Parents utilized the diverse size ofearthworms and small-sized prey of the others.

3.4. Hourly Difference of Prey Delivered in aDay
We compared the delivery rates of prey among threetime zones in a day during nestling periods. Provision
rate at a forenoon (14.7 ± 4.92) and an afternoon zone
(15.8 ± 5.30) was significantly higher than lunchtime
zone (11.7 ± 4.49, Mann-Whitney U test, Z = –1.298(forenoon and lunchtime zone, p < 0.05), Z = –1.695(afternoon and lunchtime zone, p < 0.05), Figure 4).

3.5. Staying Time of Parents at Nest During
Nestling Period
The staying time of parents in an early stage (196.4
minutes/day ± 24.56, n = 3) was far longer than otherstages of middle stage (30.4 minutes/day ± 37.17, n = 3,
p = 0.05) and late stage (6.6 minutes/day ± 2.2, n = 5, p =0.02). There was no significant difference of staying time
between middle and late stage (p = 0.07, Figure 5). So,
parents did spend about three hours in caring nestlingsand defending nests against predators during early
breeding stage.

4. DISCUSSION
4.1. Diet Composition and Prey Availability
Earthworms dominated the 82% of diet composition of
nestlings of Fairy Pitta (Figure 1). Reference [7] reported the 73% of diet ratio at Taiwan region. Earthworms can affect the breeding success of international
endangered species Fairy Pitta. Earthworms do survive
with epidermis respiration under grounds, and the bodyweight of earthworms consists of 75% - 90% of water[11], so rainfall amount and season can affect the breedCopyright © 2012 SciRes.

ing success at warm-temperate forests. The habitat ofearthworms are known to be related with the soil watercondition [12], they have a difficulty in surviving at thecondition over 35% of water contents of soil. Therefore,
earthworms emerge from undergrounds against fillingwith water at the microhabitat of ground tunnel in rainydays. Fairy pitta can sustain high detectability of earthworms in rainy days. Reference [8] reported the annual
precipitation amounts of near 3000 mm per year with
automatic logging system since 2007. Dense and mature
forests of Jeju experimental forests can affect the provision of earthworms [11,12] and the breeding success ofthe Fairy Pitta. Therefore, rainfall factors such as heavy
rainfall days over 80 mm per day from early June toearly August can affect the prey availability of Fairy Pitta
at JEFs. Comparing with the number of delivered prey
between earthworms and the others’ invertebrates, Fairy
pittas showed high using ratio of earthworms as preyresource, however, they transferred not only earthworms
and but also other invertebrates. In the percentage distribution, Invertebrates prey ranging under 4 cm occupied
the higher ratio and numbers than earthworms did (Figure 3). It suggests the possibility of diverse use of preytype in the size distribution. Endangered species do show
the specialist at the use of food resources and this specialty can affect the high extinction rate of species extermination [13], in this viewpoint Fairy Pitta seems tohave a narrow diversity in the prey use. Except earthworms invertebrates like Lepidopteran juveniles andlarvae and Coleoptera, Spiders and Slugs composed themain prey resources for nestling of Fairy Pitta (Figure 1).
Invertebrates showed high observation of species richness and density from early June to early August at JEFs
[14], so Fairy Pitta did match the breeding season at highbiomass periods of invertebrates.

4.2. Change of Caring Time for Nestlings
Parents showed the significant high staying time atearly stages than two stages they did (Figure 3). We observed that parents did care nestlings for four days after
hatching, it can be ascribed to the maintenance of air
temperature against severe weather condition at rainy
OPEN ACCESSE.-M. Kim et al. / Open Journal of Ecology 2 (2012) 178-182
10Percentage (%)

Prey size (cm)

8
6
4
2
0
Earthworms

The others

70.0
60.0
50.0
40.0
30.0
20.0
10.0
0.0
below2 3-4

181

Earthworms
The others
Total

5-6 7-8 9-10 over11
Prey size (cm)Figure 3. Average length (a) and percentage distribution (b) of prey sizes of earthworms (n = 670) and the others (n = 156), and percentage distribution of prey sizedelivered by parents Fairy Pitta (n = 826).
ns

Prey delivery number25

p < 0.05

p < 0.05

20
15
10
5
0
0500 - 0959

1000 - 1459

1500 - 1800

Daily time interval

Figure 4. Comparison of daily prey delivery among forenoon(n = 103), noon (n = 94) and afternoon (n = 111) time intervals.
p = 0.02
250
ns

Staying time (minute) per day

p = 0.05
200
150
100
50
0
Early stage

Middle stage

Late stage

Figure 5. Comparison of staying time at nest per day in three
breeding stages.

season, not to provide the prey to nestlings. In the case offorest passerine birds, number of nest visits is relatedwith the amounts of prey availability [16-18], however
Fairy pitta spent more time to caring at early stages. We
wonder if parents have a defense strategy against predator, however it is important to note the high ratio of caring time at early stages in this study area.

4.3. Comparison with the Habitat of Fairy
Pitta in Taiwan
In Taiwan, parents of Fairy pitta visited about seventy
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times per day and they showed average 1.8 number per
visit in Taiwan [7], in Korea, however they visited about
forty times (Figure 4) and they delivered about fourpreys per visit. So, there is a possibility of difference
between two regions, high visit with low prey-load in
Taiwan and high prey-load with low visit in Korea.
These phenomenon can be ascribed to the forest type(warm-temperate forests in Korea and sub-tropical forests in Taiwan) and biodiversity (relatively high and intensively networked in Taiwan), that is prey availability
and predator risk. In the viewpoint of predation risk,
there will be a high predation risk due to high biodiversity of predators in Taiwan. In Taiwan, Reference [7]reported the predators of Fairty pitta as follows; mammals (Macaque, Mongoose and Civets), snakes, birds
and ants [7]. However, we can suggest cat snake (Elaphe
dione) and Jungle crow (Corvus macrorhynchos) as predators.
Meanwhile, there was no prey belonging to vertebrates
at this area, however vertebrates including frogs, lizards,
snakes and rodents (Soricidae) dominated the 4% of preyat Taiwan area [7]. There was a presence report on theamphibians, reptiles and small rodents at JEFs, however
those vertebrates were mainly observed at the open grassland, and their occurrence rate was not so abundant [15].
Also, it seems that Fairy Pitta should spend more cost to
catch and handle these vertebrate’s preys. Comparing
with the habitat condition of Taiwan, Fairy pitta may
shift their main prey of invertebrates to vertebrates. Actually there was one time observation records (Kim EunMi,
personal communication) on the delivering the lizards tothe nests of Fairy Pitta in 2006.

4.4. Threatening Factors to the Fairy Pitta at
JEFs
As prey resources, earthworms can have a good merit
to nestlings because earthworms can be easily fragmented and a high energy sources to nestlings. Passerine
birds can digest the large-sized prey (over 4 cm) after
one week since hatching [19-21], so thrushes and someground foragers have a preference to earthworms. In fuOPEN ACCESS182

E.-M. Kim et al. / Open Journal of Ecology 2 (2012) 178-182

ture, the preference mechanisms to earthworms should
be addressed to conserve the population of Fairy pitta. In
the other viewpoint, earthworms’ density is negatively
related with the ground trampling [22], so intensity of
eco-tourisms and logging area can be detrimental to thebreeding success of Fairy pitta. Also, it was known thatover fifty-year forests can sustain high density of earthworms [22], so the conservation of over fifty-year forests
can be more effective way to conserve the internationallythreatened species. Volcanic bedrocks of study areas canhave a limit to maintain the high depth of litter layer andsoil humidity for the earthworms’ habitat, so it is essential to conserve the interaction between soil and litter
layer at JEFs.

5. ACKNOWLEDGEMENTS
This study was financially supported by forest science project grant
No. 500-20080086 of Korea Forest Service.

REFERENCES[1]

Lambert, F. and Woodcock, M. (1996) Pittas, broadbills
and asities. Pica Press, Sussex.

[2]

BirdLife International (2001) Threatened birds of Asia:
The BirdLife International red data book. BirdLife International, Cambridge.

[3]Kim, E.M. (2006) The distribution and breeding ecology
of fairy pitta (pitta nympha) on Mt. Halla. Research Institute of Mt.Hallasan, Jeju.

[4]

Kim, H.K. (1964) The ecology of fairy pitta. Bulletins of
Korea Cultural Resarch Institute, 5, 235-240.

[5]Won, P.O. (1968) Animals in Hallasan, in ministry of culture and Public information. Report on the scientific survey
on natural preserves of Mt. Hallasan and Hongdo Island,
Ministry of Culture and Public Information, Seoul.

New Jersey.
[10] R Development Core Team (2011) R: A language andenvironment for statistical computing. R Foundation for
Statistical Computing, Vienna.
[11] Satchell, J.E. (1955) Some aspects of earthworm ecology,
In: Kevan, D.K.Mc.E., Ed., Butterworths, Soil Zoology,
London, 180-201.
[12] Na, Y.E., Lee, S.B., Han, M.S., Kim, S.G. and Choi, D.R.
(2000) Soil properties influencing on earthworm habitation in upland. Korean Journal of Soil Zoology, 5, 165168.
[13] Cody, M.L. (1974) Competition and the structure of bird
communities. Princeton University Press, New Jersey.
[14] Chung, S.H., Park, J.K., Kim, J.T. and Kim, B.W. (2004)
Invertebrates. Korea Forest Research Institute, Seoul.
[15] Park, C.R., Lee, S.G., Byun, K.O., Kim, C.M., Chung,Y.G., Kim, E.M. and Jeong, S.B. (2008) An eco-guidebook to the wildlife in Jeju experimental forests. Korea
Forest Research Institute, Seoul.
[16] Naef-Daenzer, B. and Keller, L.F. (1999) The foraging
performance of great and blue tits (Parus major and P.
caeruleus) in relation to caterpillar development, and its
consequences for nestling growth and fledgling weight.
Journal of Animal Ecology, 68, 708-718.
doi:10.1046/j.1365-2656.1999.00318.x[17] Naef-Daenzer, L., Naef-Daenzer, B. and Nager, R.G.
(2000) Prey selection and foraging performance of breeding Great Tits parus major in relation to food availability.
Journal of Avian Biology, 31, 206-214.
doi:10.1034/j.1600-048X.2000.310212.x[18] Grieco, F. (2002) Time constraint on food choice in provisioning blue tits, parus caeruleus: The relationship between feeding rate and prey size. Animal Behaviour, 64,
517-526. doi:10.1006/anbe.2002.3073[19] Knapton, R.W. (1984) Parental feeding of nestling nashville warblers: The effects of food type, brood-size, nestling age, and time of day. Wilson Bull, 96, 594-602.
[20] Van Horne, B. and Bader, A. (1990) Diet of nestling winter wrens in relationship to food availability. Condor, 92,
413-420. doi:10.2307/1368238[6]

Kim, E.M., Oh, H.S., Kim, S.B. and Kim, W.T. (2003)
The distribution and habitat environment of fairy pitta(pitta nympha temminck & Schlegel) on Jeju Island, Korea. Korean Journal of Ornithology, 10, 77-86.

[7]Lin, R.S., Yao, C.T. and Lee, P.F. (2007) The diet of fairy
pitta pitta nympha nestling in Taiwan as revealed byvideotaping. Zoological Studies, 46, 355-361.

[21] Haggerty, T.M. (1992) Effects of nestling age and broodsize on nestling care in the Bachman’s Sparrow (Aimophila aestivalis). The American Midland Naturalist Journal, 128, 115-125. doi:10.2307/2426418[8]

Kim, C.M., Park, C.R., Chung, Y.G., Son, S.G., Kim, C.S.
and Kim, J. (2009) Sustainable forest management ofwarm-temperate forests. Korea Forest Research Institute,Jeju.

[22] Smetak, K.M., Johnson-Maynard, J.L. and Lloyd, J.E.
(2007) Earthworm population density and diversity indifferent-aged urban systems. Applied Soil Ecology, 37,
161-168. doi:10.1016/j.apsoil.2007.06.004[9]Zar, J.H. (1984) Biostatistical analysis. Prentice-Hall Inc.,

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