ductive value of each sex. We examined the brood sex ratio in the Lilac-crowned Parrot (Amazona finschi) in relation to climate, hatching date. El loro corona lila (Amazona finschi) es una especie endémica de la costa del Palabras clave: Amazona finschi, psitácidos, distribución. The species Amazona finschi is endemic to the Mexican coast of the Pacific Ocean status of lilac-crowned parrot (Amazona finschi) populations in Mexico was.
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Amazona finschi (Sclater ) Loro corona lila. Alejandro Salinas-Melgoza. A. Salinas-Melgoza. Loading Preview. Sorry, preview is currently unavailable. PDF | Evolutionary theory predicts birds should adjust the sex ratio of their broods in response to external factors that differentially affect the. Amazona finschi. (Sclater, ). Code A (1). Common names: engl.: Lilac-crowned Amazon, Finsch's Amazon esp.: Cotorra frente roja.
Advanced Search Abstract For —, we determined reproductive output and success of 70 Lilaccrowned Parrot Amazona finschi nests in tropical dry forest of the Chamela-Cuixmala Biosphere Reserve in western Mexico. Low brood survival in and caused significant between-year variation in the probability of nest success during the nestling phase of the nest cycle. Reproductive output of Lilac-crowned Parrots was low, with females producing an average of 0. The fecundity component of clutch size varied significantly between years, because of the high median clutch size recorded in Nestling survival also varied significantly between years, creating large interannual fluctuations in reproductive output. The most productive breeding season was , with an average output of 1.
We studied the Lilac-crowned Parrot Amazona finschi , a socially monogamous and sexually monomorphic species endemic to the tropical dry Animals that have the ability to alter the sex forest of western Mexico. Clutches are usually ratio of their offspring are predicted to do so as an small mean 5 2. Parents are expected to bias Melgoza , There is no difference in offspring sex ratio toward the gender that will nestling growth rate between first- and second- yield the greatest fitness benefits Trivers and hatched chicks; third-hatched chicks demonstrate Willard , Addison et al.
Factors shown to affect ties of survival, while fourth-hatched chicks brood sex ratio in birds include resource avail- occurred only in 1 year and all chicks died within ability Budden and Beissinger , Addison a few days of hatching Renton , Renton and et al.
Previous work has shown Radford and Blakey , and sequence of marked inter-annual variation in reproductive hatching Genovart et al. Nishiumi Lilac-crowned Parrot productivity and sex ratios from to About 20 mL of blood , which predicts manipulation of brood sex was collected when nestlings were.
Blood was stored in lysis buffer at uC investment and ensure survival of the most fit until analysis.
Purified DNA was extracted using a young. The primer multiplex of Han and females with hatching order within a clutch to et al.
PCR products were sex bias with order of hatching within clutches. A Chi-square goodness of fit test was forest of the Chamela-Cuixmala Biosphere Re- applied to identify any deviation from a 0. We used linear regression on the yearly the rainy season from June to October Bullock proportion of males with the amount of rainfall prior Lilac-crowned Parrots nest during the to egg-laying to evaluate whether sex ratio was dry season from February to May Renton and related to environmental quality.
The breeding Salinas-Melgoza , and fluctuations in rain- season was divided, for analysis of hatch date, into fall influence subsequent availability of food three hatch periods of equal length between the resources Renton , We used the earliest 26 Feb and latest 1 Apr recorded hatch amount of rainfall from June to February, the date over the 7 years, and young were assigned to a period prior to egg laying, as a proxy for period by hatch date.
We used Chi-square contin- environmental quality. We monitored 32 nesting gency table analysis to examine whether offspring attempts between and , and collected gender was associated with 1 hatching period, and 2 hatching order within a clutch first, second or third-hatched. We used nominal logistic regression to examine the effects of rainfall prior to egg-laying, hatch date, and hatch order on gender of nestlings.
TABLE 2. Frequency of male and female Lilac-crowned Parrot offspring by hatching order. Linear regression of the proportion of male First hatched 15 14 Lilac-crowned Parrot offspring produced in the population Second hatched 15 13 on the amount of rainfall prior to egg-laying over seven Third hatched 3 6 breeding seasons.
The number of males produced be required to detect significant associations.
There was a tendency to produce more do not affect the costs or benefits associated with females following periods of high rainfall Fig. The factors we evaluated have been survival was high Table 1. However, there was associated with sex ratio manipulation in strongly a sex ratio in following the highest dimorphic parrot species Trewick , Heinsohn annual rainfall of 1, mm.
Overall, the annual et al. In addition, The frequency of offspring gender was not restrictions imposed by chromosomal sex-determi- associated with date of hatching X25 5 1. Twenty-two nestlings hatched in the early primary sex ratio of their offspring Pike and Petrie period of which However, some studies suggest this con- and 14 nestlings hatched in the late period with straint can be overcome, although the mechanisms There was no association of nestling are not well understood West and Sheldon , sex ratio with hatching order X22 5 0.
However, Fish and laying, hatch date or hatch order on nestling sex Wildlife Service. Pease conducted this project while Whole Model X29 5 3. Our results did not support ment IOS to T. We thank Elizabeth the local resource hypothesis, although we Hobson and Eric Pease for helpful comments on this observed a tendency to produce more females manuscript.
However, Lilac-crowned Parrots exhibit high Sex allocation in a monomorphic seabird with a single- synchrony in nest initiation Renton and Salinas- egg clutch: test of the environment, mate quality, and Melgoza , which may limit the influence of female condition hypotheses. Behavioral Ecology and Sociobiology — AND S. Against the significant association of sex ratio with hatching odds?
Nestling sex ratio variation in Green-rumped order, although our data indicate a slight female- Parrotlets. Behavioral Ecology — Climate of Chamela, Jalisco, and dimorphic Common Kestrel Falco tinnunculus trends in the south coastal region of Mexico.
Studies of vocal communication of Psittaciformes report from five to 15 calls that can be classified in discrete spectrographic or structural categories [ 12 , 13 , 17 , 19 — 21 , 23 — 28 ], where some vocalisations are given in a variety of contexts, but other vocalisations may be specific to a given behavioural context [ 19 — 21 , 23 — 25 , 27 , 29 ]. In particular, van Horik et al. Selection forces may drive the form or characteristics of vocal signals in accordance with signal design rules to attain optimal communication in a given behavioural context [ 3 ].
Design rules state that signals used in differing behavioural contexts should present features of range, locatability, duty cycle duration and repetition rate , sender identification, within-individual variation, and form-content linkage that optimise coding of the information to be conveyed [ 3 ]. The importance of vocal communication in psittacine behaviour and social organisation is reflected by the fact that parrots use vocal signals in a variety of behavioural contexts, yet to date no studies have conducted across-function comparisons of parrot acoustic signals in differing social contexts to identify the combination of design features that could optimise communication, and whether these conform to signal design rules.
Parrots use vocalisations of contrasting characteristics, with long-range acoustic signals where energy is concentrated at low frequencies, and short-range signals of high frequencies [ 22 , 24 , 27 ], suggesting that some design rules may be at play.
Behavioural studies of the Lilac-crowned Amazon Amazona finschi indicate that vocal signals are used to coordinate nesting behaviour by the reproductive pair [ 30 ].
However, the characteristics of the vocal repertoire, context specificity of vocalisations, and how these conform to signal design rules, are still unknown. Therefore, in the present study we statistically characterised the vocal repertoire of free-living Lilac-crowned Amazons in distinct behavioural contexts.
In accordance with signal design rules [ 3 ], we hypothesised that alarm vocalisations would be context-specific, having acoustic characteristics of either flee low, short, single vocalisation or assembly loud, broad, repeated signals. On the other hand, aggressive threat signals should be more complex being either loud or soft, involve counter-calling, and have characteristics to encode information on body size or motivation.
Similarly, nesting vocalisations should be directed at a specific receiver or nest-site, have a high duration or repetition rate, with a diverse repertoire, where both the male and female participate.
Finally, we expected vocalisations emitted when perched or foraging to be of short-range, with low diversity and repetition rate, so as to maintain contact with conspecifics but avoid detection by potential predators. The main vegetation types within the reserve are dense deciduous forest on the hills and slopes, and taller semi-deciduous forest in valleys [ 33 ].
The Lilac-crowned Amazon is endemic to the Pacific coast of Mexico, and nests during the dry season from February to May [ 30 ]. Vocal recording We recorded vocalisations emitted by parrots at nest-sites, and during opportunistic encounters while they were foraging and resting.
Recordings were saved on secure digital or compact flash cards as bitwav files, with a sampling rate of Recordings were viewed via spectrogram in Raven Pro 1. Vocal analyses We reviewed recordings to extract notes, defined as a continuous sound bordered by a silent interval [ 36 ]. ACMM then conducted visual comparison of spectrograms for each note to classify notes in different types. Although we carried out a full account of all notes emitted to evaluate the diversity of acoustic signals, we selected only note-types emitted more than once to describe vocalisations.
For statistical analysis we used only note-types that were emitted at least five times across all recordings, and randomly selected five high-quality notes, with low background noise and a high signal-to-noise ratio, for each note-type.
We measured five spectrographic variables in Raven Pro 1. We thereby obtained a total of 11 variables for each note. Vocalisations were associated with nine behavioural contexts [ 7 , 19 , 20 , 24 , 27 ]: 1 Nesting activity, when the male returned to the nest after foraging, and called the incubating female who vocalised on leaving the nest-cavity to be fed [ 30 ]; 2 Threat interactions of agonistic encounters between conspecifics, usually around the nest; 3 Alarm vocalisations emitted in the presence of potential predators; 4 Foraging, emitted by individuals while foraging in trees; 5 Perched, when parrots were perched inactive or at rest in a tree; 6 Take-off, vocalisations emitted seconds before, during and after flight take-off by parrots; 7 Flight, obtained from flying parrots; 8 Landing, vocalisations of parrots on final flight approach to land in a tree; and 9 Food soliciting, begging by nestlings soliciting food from parent birds, and nesting females soliciting food from males.
Given the difficulties of capturing and marking free-ranging parrots, we considered individual identification based on nest-site ownership for recordings obtained at nest sites. Reproductive pairs of Lilac-crowned Amazons are highly synchronous in nesting behaviour [ 30 ]. Therefore for many of the behavioural contexts we used vocalisations recorded at different nest-sites where we could be confident of individual identification.
For recordings of behavioural contexts away from nest-sites foraging, flight , we used only recordings obtained on different days and those that were sufficiently separated by distance among sites to potentially represent different individuals, considering the daily foraging distances travelled by Lilac-crowned Amazons [ 38 ].
We were able to distinguish between male and female parrots at nests, as only the female incubates [ 30 ]. Statistical analyses A third of note-types were emitted only once, and were not considered in further analyses, leaving a total of notes that comprised note-types emitted at least twice.
For each of the nine behavioural contexts, we determined the emission rate of notes per second, calculated as the total number of notes emitted divided by time from when the first note was emitted to the last note for that context, which was used as a measure of intensity of vocal activity during the recording period for each behavioural context.
We also determined the frequency of occurrence of the most common note-types emitted by adult parrots across all recordings in each behavioural context, and applied chi-square contingency table analysis to determine whether note-types were associated with a specific behavioural context.
We calculated adjusted standardised residuals for each cell [ 39 ] to determine which notes were used more than expected in each context. For statistical analyses of acoustic parameters, we eliminated 43 note-types that were emitted less than five times, or had poor quality recordings with a lot of background noise or overlapped other notes.
This gave a total of 58 note-types of sufficient sound quality and frequency of emission that were used in statistical parameter analyses among behavioural contexts. We used Generalised Linear Mixed Models GLMM fit by maximum likelihood, where we considered behavioural context as a fixed effect, and included individual identity as a random effect across contexts.