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Cettia cettiCetti's warbler

By Skye Jarskey

Geographic Range

The Cetti’s warbler is located in the Palearctic region; it has a widespread geographic range across the majority of Southern Eurasia as well as northern Africa and Mediterranean Islands. During the winter season Cetti’s warbler relocates to subtropical climate zones such as Afghanistan, Iran, Pakistan, and Iraq. Breeding tends to take place near water basins, primarily in lowlands but occasionally in mountain valleys as high as 2450 meters. (Baker, 1997; "Cettia cetti albiventris (Cetti's Warbler (albiventris)) - Avibase", 2020; "Cettia cetti orientalis (Cetti's Warbler (orientalis)) - Avibase", 2020)

Habitat

Cetti’s warbler prefer areas with thick vegetation in which they use to perch and hide. They spend most of their time near the ground and in shrubs and hedges; they use short hops or fast, low bursts of whirling flight to go from bush to bush. Cetti’s warblers can be found at elevations ranging from below 100 meters to an extreme 2450 meters on rare occasions. They are most commonly found near bodies of water including rivers and streams. Nests are built inside lifeless, dry bushes, ranging from 24 to 195 cm off the ground. (Baker, 1997; "Cetti's Warbler - eBird", 2020; Tasinazzo, 1993)

  • Range elevation
    100 to 2450 m
    328.08 to 8038.06 ft

Physical Description

Size is the only sexually dimorphic characteristic of the Cetti's warbler. Males are larger by approximately 11.2-13.5% by wing length and are 26-32% heavier than females. Wing lengths of male Cetti’s warblers are about 58 to 67 mm in length whereas females are between 51 and 61 mm. The average weight of a male is in the range of 10 and 18.5 grams while females average between 8 and 16.5 grams. Cetti’s warbler has a chestnut brown coloration with olive undertones on its forehead, crown and nape. The lower back, rump and uppertail-coverts have a more russet coloration. The supercilium on Cetti’s warbler is a greyish-white tone. Flight feathers as well as the tail are a darker black-brown whereas the chin, throat and belly are white. The bill is a dark brown and the base of the lower mandible is a pale brown. The legs of the Cetti’s warbler can be light pink, light brown, or a light russet. Juveniles have weaker coloration with lighter browns and off whites being presented instead of russets and grey-whites. The subspecies C.c. orientalis has an overall lighter coloration than C.c. albiventris. (Baker, 1997; Bibby and Thomas, 1984; "Cetti's Warbler - eBird", 2020)

  • Sexual Dimorphism
  • male larger
  • Range mass
    8 to 18.5 g
    0.28 to 0.65 oz
  • Range wingspan
    51 to 67 mm
    2.01 to 2.64 in

Reproduction

Cetti’s warbler express polygynous mating; males breed with as many as three females per season. Their breeding range spans most of the Mediterranean. During mating, Cetti’s warblers copulate in bushes surrounding reed beds and will only enter the reed bed after mating. The males claim an area of land as their territory, they patrol and protect this area using a variety of vocalizations. Song type I is only used by males when they are in a territorial dispute with other breeding males. Song type S is sung by male birds regularly to express the perimeter of his territory. The song type that a male uses is determined by his level of aggression. Although males have territories of varying sizes this does not impact the amount of females they breed with. The size of the male’s body determines his harem size. (Balanca and Schaub, 2005; Bibby, 1982; Luschi, 1994; Tasinazzo, 1993)

The breeding season of Cetti’s warbler begins in late March to mid-April and lasts until early August. Cetti's warbler have an average clutch size of about four eggs, however later in the breeding season clutch size decreases. Females that are a part of a polygynous mating have larger clutch sizes than females who are monogamous. Older females are more successful at breeding as well as rearing their young in comparison to one year old breeding females. Most females only have one clutch per breeding season, however, they will lay a second clutch if the first is unsuccessful. Females who lay their eggs in early spring have increased success in rearing their young. Eggs are incubated by the females only, and the females are the primary care-takers of the young. Males that breed with less females may partake in the feeding of the young, but this does not significantly impact the amount of food that is brought to the hatchlings. (Araujo, et al., 2016; Bibby, 1982; Luschi, 1994; Tasinazzo, 1993)

  • Breeding interval
    Once yearly
  • Breeding season
    Begins in late March to mid-April and ends in early August
  • Range eggs per season
    3 to 5
  • Average time to hatching
    16 days
  • Average fledging age
    1 months
  • Range age at sexual or reproductive maturity (female)
    1 (low) years

Male Cetti's warblers protect their territory for the entirety of the breeding season. This allows for the males to protect all of the nests in his harem throughout the entirety of the breeding season. Males that have less reproducing females will assist in post-birthing care by bringing additional resources to the offspring. Females protect the young by maintaining the nest. The females incubate the nest alone for about 16 days. After the eggs hatch, females are the primary caretakers of the young. (Bibby, 1982; Tasinazzo, 1993)

  • Parental Investment
  • female parental care
  • pre-fertilization
    • protecting
      • male
  • pre-hatching/birth
    • protecting
      • male
  • pre-weaning/fledging
    • provisioning
      • female
  • pre-independence
    • provisioning
      • female

Lifespan/Longevity

Lifespan is not reported in the literature.

Behavior

Cetti’s warblers are mostly non-migratory birds that stay in Southern Europe, especially Mediterranean areas. This species stays relatively close to the ground in thick foliage and they have a short hopping gate. Cetti’s warblers live a sessile lifestyle for a bird. They usually only fly in a low whirling fashion to move from bush to bush. Male Cetti’s warblers are more active, especially during the breeding season. They will fly around their territory and perch in open bushes. Their loud songs make them easier to locate as they defend their territory. (Baker, 1997; Bibby and Thomas, 1984; Lushi and Seppia, 1996)

  • Average territory size
    10 km^2

Home Range

Female and juvenile Cettia’s warblers will disperse further than males as males stay in their territories year round. Once juvenile males find an area to be there territory they will stay there, likely for most of their life. Male territories range in size and shape depending on the bird. Cetti’s warblers are sessile in nature, they only travel about 10 km in distance. Their territory availability is limited to areas that have reed swamps. This specific type of habitat is becoming increasingly rare and patchy in nature, especially in Britain. (Araujo, et al., 2016; Robinson, et al., 2007)

Communication and Perception

Cetti’s warblers use acoustic ques to communicate, this is especially prevalent in males. There are two primary song types used by males, song type S and song type I. Song type S is a song of consistent staccato notes. Each male exhibits his own unique kind of song type S. Typically, males sing there song once from one area of cover and then change their location before singing again. Song type I is an inconsistent song that is not used by males in normal settings. Song type I is only used when males exhibit territorial behaviors. ("Cetti's Warbler - eBird", 2020; Lushi and Seppia, 1996; Zvonov, 2004)

Food Habits

The main food source for Cetti’s warbler is insects. The warblers spend their time foraging for these insects in reedbeds, which have a high abundance of predator insects, insects that consume other invertebrates. These predator insects, especially Coleoptera and Hymenoptera, make up the majority of the Cetti’s warblers diet. Other types of insects are also consumed and the main source may change with seasonal changes. Cetti’s warblers that spend most of their time in riparian areas may also consume seeds in addition to insects. (Araujo, et al., 2016; Baker, 1997)

  • Animal Foods
  • insects
  • Plant Foods
  • seeds, grains, and nuts

Predation

Cetti’s warblers are susceptible to predation by avian predators and human game hunters. Male Cetti’s warbler are at a higher risk of predation during the breeding season. The polygynous males spend more time flying and singing to announce their presence and the perimeter of their territory during the breeding season. These actions make them more at risk for aerial predation. Females are at higher risk for predation in the non-breeding season. Male Cetti’s warblers usually stay in their breeding territories during the non-breeding season. These areas have an abundance of coverage and resources available and they are used to the area, making it harder for predators to access the males. However, the females and juveniles are forced out of the breeding areas into new areas. These new areas are usually of less coverage and with lesser food resources making it easier for predators to access these birds. The overall coloration of this species allows it to blend in easily with its habitat, making it more difficult to be seen by predators. (Araujo, et al., 2016; Baker, 1997; Bibby, 1982)

  • Anti-predator Adaptations
  • cryptic

Ecosystem Roles

Cetti’s warbler’s primary ecosystem role is the regulation of reed bed insects such as damsel flies and invertebrate larvae. As one of the primary food sources for Cetti’s warbler insect populations are kept to a reduced number in the ecosystem. Cetti’s warblers also play a minor role in seed distribution. Cetti’s warblers are carriers of avian haemoparasites that are commonly found in reed bed passerines. They have been found to carry multiple types of parasites in the genera Haemoproteus and Plasmodium. Haemoproteus includes hippoboscid flies, biting midges or tabanids. These parasites can show little to mild clinical symptoms in their hosts and rarely require treatment. Plasmodium are blood parasites that can cause malaria in the hosts. This parasite is transmitted from mosquitos to vertebrate hosts. (Araujo, et al., 2016; Baker, 1997; Tully, 2009; Ventim, et al., 2012)

  • Ecosystem Impact
  • disperses seeds
Commensal/Parasitic Species
  • Haemoproteus and Plasmodium

Economic Importance for Humans: Positive

There has been little to no research done on the economic importance of Cetti’s warbler. Although they have been used to restore and promote the conservation of reed beds. (Bibby and Lunn, 1981)

  • Positive Impacts
  • research and education

Economic Importance for Humans: Negative

Cetti’s warbler has been connected to the spread of infectious diseases to mankind. Salmonella Napoli. was found in high concentrations within Cetti’s warblers populations. Nearly 1 in 6 birds were found to have this bacteria. This has been linked to a multitude of food associated outbreaks throughout Europe, typically with an Italian origin. In addition to Salmonella Napoli, Cetti’s warblers have also been linked to the spread of hemorrhagic diseases in humans. During times of migration Cetti’s warbler has been found to carry the Crimean-Congo Hemorrhagic Fever which has largely impacted Turkey. (Leblebicioglu, et al., 2014; Mancini, et al., 2014)

Conservation Status

This species is at a low conservation concern, it is of Least Concern according to the IUCN Red List. Currently there are over 4,050,000 breeding individuals in the wild. The greatest threat to this species is global climate changes which could affect the distribution of this species and their habitat availability. ("The IUCN Red List of Threatened Species", 2020)

Contributors

Skye Jarskey (author), Northern Michigan University, Alec Lindsay (editor), Northern Michigan University.

Glossary

Palearctic

living in the northern part of the Old World. In otherwords, Europe and Asia and northern Africa.

World Map

acoustic

uses sound to communicate

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

carnivore

an animal that mainly eats meat

causes disease in humans

an animal which directly causes disease in humans. For example, diseases caused by infection of filarial nematodes (elephantiasis and river blindness).

chemical

uses smells or other chemicals to communicate

cryptic

having markings, coloration, shapes, or other features that cause an animal to be camouflaged in its natural environment; being difficult to see or otherwise detect.

diurnal
  1. active during the day, 2. lasting for one day.
endothermic

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

female parental care

parental care is carried out by females

granivore

an animal that mainly eats seeds

herbivore

An animal that eats mainly plants or parts of plants.

insectivore

An animal that eats mainly insects or spiders.

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

motile

having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.

omnivore

an animal that mainly eats all kinds of things, including plants and animals

oviparous

reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.

polygynous

having more than one female as a mate at one time

polymorphic

"many forms." A species is polymorphic if its individuals can be divided into two or more easily recognized groups, based on structure, color, or other similar characteristics. The term only applies when the distinct groups can be found in the same area; graded or clinal variation throughout the range of a species (e.g. a north-to-south decrease in size) is not polymorphism. Polymorphic characteristics may be inherited because the differences have a genetic basis, or they may be the result of environmental influences. We do not consider sexual differences (i.e. sexual dimorphism), seasonal changes (e.g. change in fur color), or age-related changes to be polymorphic. Polymorphism in a local population can be an adaptation to prevent density-dependent predation, where predators preferentially prey on the most common morph.

seasonal breeding

breeding is confined to a particular season

sedentary

remains in the same area

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

tactile

uses touch to communicate

terrestrial

Living on the ground.

territorial

defends an area within the home range, occupied by a single animals or group of animals of the same species and held through overt defense, display, or advertisement

visual

uses sight to communicate

References

2020. "Cetti's Warbler - eBird" (On-line). eBird. Accessed April 16, 2020 at https://ebird.org/species/cetwar1.

2020. "Cettia cetti albiventris (Cetti's Warbler (albiventris)) - Avibase" (On-line). Accessed April 17, 2020 at https://avibase.bsc-eoc.org/species.jsp?lang=EN&avibaseid=DAACD4B3F7E09C47&sec=map.

2020. "Cettia cetti orientalis (Cetti's Warbler (orientalis)) - Avibase" (On-line). Accessed April 17, 2020 at https://avibase.bsc-eoc.org/species.jsp?lang=EN&avibaseid=8784DE66&sec=map.

2020. "The IUCN Red List of Threatened Species" (On-line). Accessed January 31, 2020 at https://www.iucnredlist.org/en.

Araujo, P., P. Lopes, L. da Silva, J. Ramos. 2016. The Importance of Reedbeds and Riparian Areas for Cetti’s Warbler Cettia cetti throughout its Annual Cycle. Wetlands, 36/5.

Baker, K. 1997. Warblers of Europe, Asia and North Africa. A&C Black.

Balanca, G., M. Schaub. 2005. Post-breeding migration ecology of Reed Acrocephalus scirpaceus, Moustached A. melanopogon and Cetti’s Warblers Cettia cetti at a Mediterranean stopover site. Ardea, 93/2.

Bibby, C. 1982. Polygyny and Breeding Ecology of the Cetti's Warbler Cettia Cetti. Ibis, 124/3.

Bibby, C., J. Lunn. 1981. Conservation of reed beds and their avifauna in England and Wales. Biological Conservation, 23/3: 167-189.

Bibby, C., D. Thomas. 1984. Sexual dimorphism in size, moult and movements of Cetti's Warbler Cettia cetti. Bird Study, 31/1.

Leblebicioglu, H., C. Eroglu, K. Erciyas-Yavuz, M. Hokelek, M. Acici, H. Yilmaz. 2014. Role of Migratory Birds in Spreading Crimean-Congo Hemorrhagic Fever, Turkey. Emerging Infectious Disease, 20/8.

Luschi, P. 1994. Responses of territorial male Cetti's warblers (Cettia cetti) to playback of different song‐types. Italian Journal of Zoology.

Lushi, P., C. Seppia. 1996. Song-type function during territorial encounters in male Cetti's Warblers Cettia cetti. Ibis, 138/3.

Mancini, L., S. Marcheggiani, A. D'Angelo, C. Puccinelli, F. Chiudioni. 2014. First isolation of Salmonella enterica serovar Napoli from wild birds in Italy. Ann. Ist. Super. Sanità, 50: 96-98.

Robinson, R., S. Freeman, D. Balmer, M. Grantham. 2007. Cetti's Warbler Cettia cetti: analysis of an expanding population. Bird Study, 54: 230-235.

Tasinazzo, S. 1993. Breeding ecology of Cetti's warbler (Cettia cetti, Aves) in northeastern Italy. Bollettino di zoologia, 60/2.

Tully, T. 2009. Handbook of Avian Medicine. Elsevier.

Ventim, R., J. Morais, S. Pardel, L. Mendes, J. Ramos, J. Perez-Tris. 2012. Host-parasite associations and host-specificity in haemoparasites of reed bed passerines. Parasitology, 139/3: 310-316.

Zvonov, B. 2004. Principles of Acoustic Communication between Man and Birds. Biology Bulletin, 31/2: 151-158. Accessed February 16, 2020 at https://doi.org/10.1023/B:BIBU.0000022470.35794.6d.

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