The Upupidae family, commonly known as hoopoes, is a group of birds belonging to the order Coraciiformes, which comprises a single species, Upupa epops, commonly known as the common hoopoe or European hoopoe. This bird is known for its distinctive plumage, erect crest, and curious behavior. Although the family is represented by only one species, the common hoopoe is widely distributed in Eurasia and North Africa, and it is recognizable for its unique behavior and fascinating appearance.
Scientific Classification
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Coraciiformes
Family: Upupidae
Genus: Upupa
Species: Upupa epops
Morphological Characteristics
The common hoopoe is a medium-sized bird, ranging in length from 25 to 32 cm. It is easily recognizable by its erect crest, which, when raised, is one of its most noticeable features. The hoopoe's plumage is generally light brown with black striping, with more vivid tones on the head and tail. Its beak is long, thin, and curved, adapted for digging into the ground to search for insects and invertebrates. Its wings are long and rounded, and the tail is relatively long and pointed.
The plumage of the crest consists of long, thin feathers, which the bird can raise into an elegant tuft when excited or during courtship. Plumage colors can vary slightly depending on the season and geography, but they generally feature beige, brown, and white tones, with black striations on the wings and head.
Behavior and Feeding Habits
The common hoopoe is primarily insectivorous, feeding on a variety of insects, including ants, beetles, cockroaches, and other small invertebrates. Its long, curved beak allows it to probe the ground and tree bark in search of food. Although a terrestrial bird, the hoopoe is also a skilled flyer and moves quickly from one place to another when searching for food or during migration.
The hoopoe is known for its solitary foraging behavior, which includes searching for insects in the ground, under bark, or in low bushes and plants. It may also be seen raising its crest as part of its courtship behavior or during interactions with other birds.
Habitat and Distribution
The common hoopoe is primarily found in Europe, Asia, and North Africa, but it can also be found in some areas of the Middle East and some islands in the Indian Ocean. Its ideal habitat includes open land, gardens, meadows, forests with sparse trees, and agricultural land. The hoopoe is often seen in agricultural environments, where it can forage between crops or in urban gardens and parks.
During the winter season, many populations migrate south, particularly to Africa, to avoid the harsh winter conditions of colder regions of Eurasia. However, some populations are sedentary in more temperate regions, especially in the southern parts of their range.
Reproduction
The breeding season of the common hoopoe mainly occurs in spring and summer. Males court females by raising their crest and producing melodic calls, which are one of the distinctive aspects of this species. After mating, the pair builds their nest in tree cavities, holes in the ground, or ruined walls. The female generally lays between 4 and 7 eggs, which are incubated by both parents for about 15 days.
The parents care for the chicks, feeding them primarily insects and other small invertebrates until they are large enough to fly and forage independently. Parental care is strong, with both parents actively participating in feeding and protecting the chicks.
Conservation
The common hoopoe is generally considered a species of low conservation concern, but some local populations are threatened by habitat loss, deforestation, and the use of pesticides, which reduce the availability of food. The destruction of agricultural land and urbanization of natural areas threaten the hoopoe's habitat, although the species remains relatively abundant in many regions.
Protecting natural habitats and conserving traditional agricultural areas are essential to ensure that the common hoopoe continues to thrive, particularly in areas where populations are more vulnerable.
Conclusion
The Upupidae family, represented primarily by the common hoopoe (Upupa epops), is an extraordinary example of adaptation to open environments and the search for food in the ground and low plants. With its distinctive plumage, erect crest, and solitary, insectivorous behavior, the hoopoe remains a fascinating and easily recognizable species. Although not globally considered threatened, conserving its natural habitat is essential to ensure its long-term survival in many areas.
References__________________________________________________________________________
Díaz-Lora S, Pérez-Contreras T, Azcárate-García M, Peralta-Sánchez JM, Martínez-Bueno M, José Soler J, Martín-Vivaldi M. Cosmetic coloration of cross-fostered eggs affects paternal investment in the hoopoe (Upupa epops). Proc Biol Sci. 2021 May 12;288(1950):20203174. doi: 10.1098/rspb.2020.3174.
Abstract. The signalling hypothesis suggests that avian eggshell coloration is a sexually selected female signal advertising her quality to its male partner, thereby stimulating his provisioning rate. This hypothesis has been tested for structural eggshell pigments, but not for cosmetic colorations, such as that produced by the uropygial secretion on eggshells. During the breeding season, female hoopoes (Upupa epops) host in their uropygial glands symbiotic bacteria. Females actively smear the eggshells with their secretion, protecting embryos from pathogenic trans-shell infections and changing eggshell coloration. Because the colour of the secretions is related to their antimicrobial potential, cosmetic eggshell coloration may act as a cue or even as a post-mating sexually selected signal if it affects male provisioning rates. To experimentally test this hypothesis, we cross-fostered already-smeared clutches between hoopoe nests, and quantified male feeding behaviour to females before and after the experiment. This approach allows disentanglement of the effects of female quality and of egg coloration on male investment. In accordance with the hypothesis, males adjusted their provisioning rate to the eggshell cosmetic coloration. This is, to our knowledge, the first experimental demonstration that egg colour stained with uropygial secretion could act as a post-mating sexual signal of female quality to males.
Soler JJ, Martín-Vivaldi M, Nuhlíčková S, Ruiz-Castellano C, Mazorra-Alonso M, Martínez-Renau E, Eckenfellner M, Svetlík J, Hoi H. Avian sibling cannibalism: Hoopoe mothers regularly use their last hatched nestlings to feed older siblings. Zool Res. 2022 Mar 18;43(2):265-274. doi: 10.24272/j.issn.2095-8137.2021.434.
Abstract. Sibling cannibalism is relatively common in nature, but its evolution in birds and certain other vertebrates with extended parental care had been discarded. Here, however, we demonstrate its regular occurrence in two European populations of the Eurasian hoopoe (Upupa epops) and explore possible adaptive and non-adaptive explanations. Results showed that sibling cannibalism was more frequently detected in Spain (51.7%) than in Austria (5.9%). In these two populations, the hoopoes laid similar clutch sizes, resulting in similar fledging production, but hatching failures were more frequent in the northern population. Consequently, having more nestlings condemned to die in the southern population may explain the higher incidence of sibling cannibalism. In accordance with this interpretation, hatching span and failure, but not breeding date, explained the probability of sibling cannibalism in the Spanish hoopoes, while all three variables predicted brood reduction intensity. Furthermore, experimental food supply reduced the probability of sibling cannibalism, but not the intensity of brood reduction. Finally, females allocated fewer resources to the smallest nestlings when they were going to starve, but not necessarily when they were going to be used as food for their siblings. These results suggest that hoopoes produce extra eggs that, in the case of reduced hatching failure and food scarcity, produce nestlings that are used to feed older siblings. These findings provide the first evidence that sibling cannibalism occurs regularly in a bird species, thus expanding our evolutionary understanding of clutch size, hatching asynchrony, parent-offspring conflict, infanticide, and sibling cannibalism in the animal kingdom.
Plard F, Arlettaz R, Schaub M. Hoopoe males experience intra-seasonal while females experience inter-seasonal reproductive costs. Oecologia. 2018 Mar;186(3):665-675. doi: 10.1007/s00442-017-4028-8.
Abstract. Reproductive and survival costs due to reproductive investment are a central element for the evolution of life histories. Both intra- (reduction of reproductive performance of second brood due to investment in first brood) and inter-seasonal costs (reduction of reproductive performance or annual survival due to reproductive investment in preceding year) may appear in multiple breeding species. Knowledge about how trade-offs within and between seasons shape individual trajectories and influence fitness are crucial in life-history evolution, yet intra- and inter-seasonal reproductive costs are rarely analysed simultaneously. We investigated sex-specific differences in intra- and inter-seasonal reproductive and survival costs in response to previous reproductive effort in a monogamous, double-brooding bird, the hoopoe (Upupa epops), accounting for heterogeneity in individual and annual quality. Intra-seasonal reproductive costs were detected in males and inter-seasonal reproductive and survival costs were detected in females. In males, the probability of being a successful double breeder was negatively correlated with the number of hatchlings produced in the first brood. In females, the number of fledglings raised in the first brood was negatively correlated with the reproductive effort in the preceding season. Female annual survival was also negatively influenced by the number of broods produced in the previous reproductive season. Most of these reproductive costs were detected only in years with low productivity, suggesting that costs become evident when environmental conditions are harsh. Our results illustrate how different investment in current vs. future reproduction and survival shape different life-history strategies in males and females of a monogamous bird species.
Soler JJ, Martín-Vivaldi M, Peralta-Sánchez JM, Arco L, Juárez-García-Pelayo N. Hoopoes color their eggs with antimicrobial uropygial secretions. Naturwissenschaften. 2014 Sep;101(9):697-705. doi: 10.1007/s00114-014-1201-3.
Abstract. Uropygial gland secretions are used as cosmetics by some species of birds to color and enhance properties of feathers and teguments, which may signal individual quality. Uropygial secretions also reach eggshells during incubation and, therefore, may influence the coloration of birds' eggs, a trait that has attracted the attention of evolutionary biologists for more than one century. The color of hoopoe eggs typically changes along incubation, from bluish-gray to greenish-brown. Here, we test experimentally the hypothesis that dark uropygial secretion of females is responsible for such drastic color change. Moreover, since uropygial secretion of hoopoes has antimicrobial properties, we also explore the association between color and antimicrobial activity of the uropygial secretion of females. We found that eggs stayed bluish-gray in nests where female access to the uropygial secretion was experimentally blocked. Furthermore, experimental eggs that were maintained in incubators and manually smeared with uropygial secretion experienced similar color changes that naturally incubated eggs did, while control eggs that were not in contact with the secretions did not experience such color changes. All these results strongly support the hypothesis that female hoopoes use their uropygial gland secretion to color the eggs. Moreover, saturation of the uropygial secretion was associated with antimicrobial activity against Bacillus licheniformis. Given the known antimicrobial potential of uropygial secretions of birds, this finding opens the possibility that in scenarios of sexual selection, hoopoes in particular and birds in general signal antimicrobial properties of their uropygial secretion by mean of changes in egg coloration along incubation.
