Nest Size Matters: Common Cuckoos Prefer to Parasitize Larger Nests of Oriental Reed Warblers

Abstract BackgroundAvian brood parasites leave parental care of their offspring to foster parents. Theory predicts that parasites should select for large host nests when they have sufficient available host nests at a given time. We developed an empirical experimental design to address this hypothesis by studying nest choice of common cuckoos (Cuculus canorus) among nests of its Oriental reed warbler (Acrocephalus orientalis) hosts.ResultsWe presented two groups of experimental nests: 1) nest dyads comprise one large and one small artificial nest from reed leaves, and 2) nest triads tied together use the modified old own warbler nests including enlarged, reduced and medium sized nests to elicit parasitism by common cuckoos. We predicted that cuckoos prefer larger nests over medium sized ones, and over the smallest nest. Our experimental findings show that common cuckoo females generally prefer large nests over medium or small sized nests. Furthermore, experiments showed that cuckoo parasitism was significantly more common than in previous studies of the same warbler population.ConclusionsOur results implying that larger, taller and more exposed host nests effectively increased the probability of cuckoo parasitism.

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Common cuckoo females remove more conspicuous eggs during parasitism

Royal Society Open Science ◽

10.1098/rsos.201264 ◽

2021 ◽

Vol 8 (1) ◽

pp. 201264

Author(s):

Longwu Wang ◽

Yuhan Zhang ◽

Wei Liang ◽

Anders Pape Møller

Keyword(s):

Reed Warbler ◽

Cuculus Canorus ◽

Common Cuckoo ◽

Alternative Strategies ◽

Brood Parasites ◽

Survival Chance ◽

Egg Mimicry ◽

Egg Crypsis

Avian obligate brood parasites gain an advantage by removing the eggs of the cuckoos who have already visited the nest, which can increase the chances of survival for their offspring. Conversely, to prevent their eggs from being picked up by the next parasitic cuckoo, they need to take some precautions. Egg mimicry and egg crypsis are two alternative strategies to prevent the parasitized egg from being picked up by another parasitic cuckoo. Here, we tested whether the egg crypsis hypothesis has a preventative effect when common cuckoos ( Cuculus canorus ) parasitize their Oriental reed warbler ( Acrocephalus orientalis ) hosts. We designed two experimental groups with different crypsis effects to induce common cuckoos to lay eggs and observed whether the cuckoos selectively picked up the experimental eggs with low crypsis levels in the process of parasitism. Our results supported the egg crypsis hypothesis; the observed cuckoos significantly preferred to select the more obvious white model eggs. This shows that even in an open nest, eggs that are adequately hidden can also be protected from being picked up by cuckoo females during parasitism so as to increase the survival chance of their own parasitic eggs.

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Heterospecific alarm-call recognition in two warbler hosts of common cuckoos

Animal Cognition ◽

10.1007/s10071-019-01307-9 ◽

2019 ◽

Vol 22 (6) ◽

pp. 1149-1157 ◽

Cited By ~ 8

Author(s):

Jiangping Yu ◽

Hailin Lu ◽

Wei Sun ◽

Wei Liang ◽

Haitao Wang ◽

...

Keyword(s):

Alarm Call ◽

Alarm Calls ◽

Reed Warbler ◽

Cuculus Canorus ◽

Common Cuckoo ◽

Playback Experiments ◽

Call Recognition ◽

Accipiter Nisus ◽

Main Host ◽

The Common

Abstract Species facing similar selection pressures should recognize heterospecific alarm signals. However, no study has so far examined heterospecific alarm-call recognition in response to parasitism by cuckoos. In this study, we tested whether two sympatric host species of the common cuckoo Cuculus canorus, Oriental reed warbler Acrocephalus orientalis (ORW, main host), and black-browed reed warbler Acrocephalus bistrigiceps (BRW, rare host), could recognize each other’s alarm calls in response to cuckoos. Dummies of common cuckoo (parasite) and Eurasian sparrowhawk Accipiter nisus (predator) were used to induce and record alarm calls of the two warbler species, respectively. In the conspecific alarm-call playback experiments, ORW responded more strongly to cuckoo alarm calls than to sparrowhawk alarm calls, while BRW responded less strongly to cuckoo alarm calls than to sparrowhawk alarm calls. In the heterospecific alarm-call playback experiments, both ORW and BRW responded less strongly to cuckoo alarm calls than sparrowhawk alarm calls. BRW seemed to learn the association between parasite-related alarm calls of the ORW and the cuckoo by observing the process of ORW attacking cuckoos. In contrast, alarm calls of BRW to cuckoos were rarely recorded in most cases. BRW with low parasite pressure still developed recognition of heterospecific parasite-related alarm call. Unintended receivers in the same community should recognize heterospecific alarm calls precisely to extract valuable information.

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The common cuckoo Cuculus canorus is not locally adapted to its reed warbler Acrocephalus scirpaceus host

Journal of Evolutionary Biology ◽

10.1111/j.1420-9101.2010.02168.x ◽

2010 ◽

Vol 24 (2) ◽

pp. 314-325 ◽

Cited By ~ 9

Author(s):

J. M. AVILÉS ◽

J. R. VIKAN ◽

F. FOSSØY ◽

A. ANTONOV ◽

A. MOKSNES ◽

...

Keyword(s):

Reed Warbler ◽

Cuculus Canorus ◽

Common Cuckoo ◽

Acrocephalus Scirpaceus ◽

The Common

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Fast and furious: host aggression modulates behaviour of brood parasites

10.1101/2020.04.27.063933 ◽

2020 ◽

Cited By ~ 2

Author(s):

Václav Jelínek ◽

Michal Šulc ◽

Gabriela Štětková ◽

Marcel Honza

Keyword(s):

Brood Parasitism ◽

Egg Laying ◽

Nest Defence ◽

Great Reed Warbler ◽

Acrocephalus Arundinaceus ◽

Brood Parasite ◽

Cuculus Canorus ◽

Common Cuckoo ◽

Brood Parasites ◽

The Common

ABSTRACTAvian brood parasites pose a serious threat for hosts, substantially reducing their fitness which selects for the evolution of host defences. A classic example of a host frontline defence is mobbing which frequently includes contact attacking of brood parasites. Here, we investigated how the nest defence of a very aggressive great reed warbler (Acrocephalus arundinaceus) host influences the speed of egg-laying and egg-removing behaviour of its brood parasite – the common cuckoo (Cuculus canorus). We video-recorded 168 brood parasitic events at 102 active host nests and found that cuckoos avoided host mobbing in only 62% of cases. If hosts spotted the cuckoo at their nests, they almost always attacked it (in 91 of 104 cases), however, such attacks only rarely and temporarily prevented cuckoos from parasitizing (11 additional cases). When attacked, cuckoos parasitized host nests significantly faster and left them immediately. However, when not attacked, cuckoos frequently stayed at or near the nest suggesting that host aggression, rather than the risk of being spotted, influences the speed of brood parasitism in this species. Further, we found that cuckoos performed egg-removing behaviour in all parasitic events without regard to host aggression. As a result, cuckoos removed at least one egg during all brood parasitism events except those when an egg slipped from their beaks and fell back into the nest (in 9 of 73 cases). This indicates that egg-removing behaviour is not costly for the common cuckoo and is an essential part of its parasitism strategy, widening understanding of this currently unexplained behaviour.

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Common Cuckoo Cuculus canorus and host behaviour at Reed Warbler Acrocephalus scirpaceus nests

Ibis ◽

10.1111/j.1474-919x.2000.tb04864.x ◽

2008 ◽

Vol 142 (2) ◽

pp. 247-258 ◽

Cited By ~ 86

Author(s):

ARNE MOKSNES ◽

EIVIN RØSKAFT ◽

LISE GREGER HAGEN ◽

MARCEL HONZA ◽

CECILIE MØRK ◽

...

Keyword(s):

Reed Warbler ◽

Cuculus Canorus ◽

Common Cuckoo ◽

Acrocephalus Scirpaceus ◽

Host Behaviour

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THE RED GAPE OF THE NESTLING CUCKOO (CUCULUS CANORUS) IS NOT A SUPERNORMAL STIMULUS FOR THREE COMMON HOSTS

Behaviour ◽

10.1163/156853999501559 ◽

1999 ◽

Vol 136 (6) ◽

pp. 759-777 ◽

Cited By ~ 15

Author(s):

◽

Keyword(s):

Host Species ◽

Foster Parents ◽

Sibling Competition ◽

Cuculus Canorus ◽

Common Cuckoo ◽

Parental Preference ◽

Supernormal Stimulus ◽

Parental Preferences ◽

Main Host

AbstractThe bright red gape of the nestling common cuckoo Cuculus canorus has often been supposed to act as a supernormal stimulus to elicit provisioning from its foster parents. Parents of three main host species were tested for their response to their own nestlings with artificially reddened gapes. Robins, dunnocks and reed warblers allocated no more food to red-mouthed nestlings than to control nestlings in the same nest, and manipulations of the gape colour of whole broods of reed warblers revealed no effect on provisioning rates. Our data do not support the hypothesis that there is a universal parental preference for redder gapes in opennesting passerines, or that the bright red gape of nestling cuckoos has evolved to exploit parental preferences in these three hosts. We suggest that although mouth colour has little influence on the allocation of feeds resulting from sibling competition and begging intensity in these species, it may have a role under certain conditions.

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Killing behaviour of adult brood parasites

Behaviour ◽

10.1163/1568539x-bja10033 ◽

2020 ◽

Vol 157 (12-13) ◽

pp. 1099-1111 ◽

Cited By ~ 1

Author(s):

M. Šulc ◽

G. Štětková ◽

V. Jelínek ◽

B. Czyż ◽

A. Dyrcz ◽

...

Keyword(s):

Video Recording ◽

Camera Traps ◽

Cuculus Canorus ◽

Common Cuckoo ◽

Brood Parasites ◽

The Common

Abstract Decades of studies have revealed the striking adaptations of avian brood parasites for their unique reproductive lifestyle. Several have reported that adult brood parasites sometimes kill host nestlings, although the reasons for this behaviour remain unclear. Using continuous video-recording and camera traps, we observed the same behaviour in the common cuckoo Cuculus canorus, showing that both host and parasite nestlings can be killed. The latter has never previously been observed in cuckoos. Here, we review this phenomenon and discuss possible explanations.

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A host-race of the cuckoo Cuculus canorus with nestlings attuned to the parental alarm calls of the host species

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2005.3324 ◽

2005 ◽

Vol 273 (1587) ◽

pp. 693-699 ◽

Cited By ~ 35

Author(s):

N.B Davies ◽

J.R Madden ◽

S.H.M Butchart ◽

J Rutila

Keyword(s):

Foster Parents ◽

Alarm Calls ◽

Specific Response ◽

Host Race ◽

Reed Warbler ◽

Common Cuckoo ◽

Playback Experiments ◽

Maternal Control ◽

Host Races ◽

The Common

The common cuckoo has several host-specific races, each with a distinctive egg that tends to match its host's eggs. Here, we show that the host-race specializing on reed warblers also has a host-specific nestling adaptation. In playback experiments, the nestling cuckoos responded specifically to the reed warbler's distinctive ‘churr’ alarm (given when a predator is near the nest), by reducing begging calls (likely to betray their location) and by displaying their orange-red gape (a preparation for defence). When reed warbler-cuckoos were cross-fostered and raised by two other regular cuckoo hosts (robins or dunnocks), they did not respond to the different alarms of these new foster-parents. Instead, they retained a specific response to reed warbler alarms but, remarkably, increased both calling and gaping. This suggests innate pre-tuning to reed warbler alarms, but with exposure necessary for development of the normal silent gaping response. By contrast, cuckoo chicks of another host-race specializing on redstarts showed no response to either redstart or reed warbler alarms. If host-races are restricted to female cuckoo lineages, then chick-tuning in reed warbler-cuckoos must be under maternal control. Alternatively, some host-races might be cryptic species, not revealed by the neutral genetic markers studied so far.

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Cuckoos use host egg number to choose host nests for parasitism

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2020.0343 ◽

2020 ◽

Vol 287 (1928) ◽

pp. 20200343 ◽

Cited By ~ 2

Author(s):

Longwu Wang ◽

Canchao Yang ◽

Gangbin He ◽

Wei Liang ◽

Anders Pape Møller

Keyword(s):

Field Experiment ◽

Parental Care ◽

Field Observations ◽

Reed Warbler ◽

Cuculus Canorus ◽

Common Cuckoo ◽

Host Nest ◽

Laying Sequence ◽

Egg Number ◽

The Right

To maximize their offspring success common cuckoo ( Cuculus canorus ) females should lay their eggs into host nests before incubation has begun. This ensures that the parasite chick hatches before all host chicks and can evict its foster siblings to monopolize host parental care. Many studies have demonstrated that most cuckoo eggs are indeed laid before the onset of host incubation. But cues used by female cuckoos to choose the right nest at the right time remain unclear. Here, we combine field observations with a field experiment to test whether female cuckoos use the number of eggs in the nests of their Oriental reed warbler ( Acrocephalus orientalis ) hosts to direct their choice. Over 8 years of field observations and 5 years of experiments, cuckoo females placed the majority of their eggs in nests with fewer than three host eggs, i.e. early in the laying sequence. For natural nests, the cuckoos may use information gleaned from the activity and behaviour of the host parents to make their choice. In our sets of experimental nests containing different numbers of model eggs, the vast majority of parasitism events occurred in nests containing a single egg. To our knowledge, this is the first field experiment showing that cuckoos choose host nests for parasitism based on the number of host eggs they contain. It appears that cuckoo females use the egg number to estimate the appropriate host nest stage for timely parasitism.

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