Upper bill bending as an adaptation for nectar feeding in hummingbirds.

Observations of maxillary (upper bill) bending in hummingbirds have been considered an optical illusion, yet a recent description of out-of-phase opening and closing between their bill base and tip suggests a genuine capacity for bill bending. We investigate bill kinematics during nectar feeding in six species of hummingbirds. We employed geometric morphometrics to identify bending zones and combined these data with measurements of bill flexural rigidity from micro-computed tomography scans to better understand the flexing mechanism.

Nectar feeding beyond the tongue: hummingbirds drink using phase-shifted bill opening, flexible tongue flaps and wringing at the tips.

Hummingbirds are the most speciose group of vertebrate nectarivores and exhibit striking bill variation in association with their floral food sources. To explicitly link comparative feeding biomechanics to hummingbird ecology, deciphering how they move nectar from the tongue to the throat is as important as understanding how this liquid is collected. We employed synced, orthogonally positioned, high-speed cameras to describe the bill movements, and backlight filming to track tongue and nectar displacements intraorally.

Bene"fit" Assessment in Pollination Coevolution: Mechanistic Perspectives on Hummingbird Bill-Flower Matching.

One of the reasons why flowering plants became the most diverse group of land plants is their association with animals to reproduce. The earliest examples of this mutualism involved insects foraging for food from plants and, in the process, pollinating them. Vertebrates are latecomers to these mutualisms, but birds, in particular, present a wide variety of nectar-feeding clades that have adapted to solve similar challenges.

Intrasexually selected weapons.

We propose a practical concept that distinguishes the particular kind of weaponry that has evolved to be used in combat between individuals of the same species and sex, which we term intrasexually selected weapons (ISWs). We present a treatise of ISWs in nature, aiming to understand their distinction and evolution from other secondary sex traits, including from 'sexually selected weapons', and from sexually dimorphic and monomorphic weaponry. We focus on the subset of secondary sex traits that are the result of same-sex combat, defined here as ISWs, provide not previously reported evolutionary patterns, and offer hypotheses to answer questions such as: why have only some species evolved weapons to fight for the opposite sex or breeding resources? We examined traits that seem to have evolved as ISWs in the entire animal phylogeny, restricting the classification of ISW to traits that are only present or enlarged in adults of one of the sexes, and are used as weapons during intrasexual fights.

Environmental enrichment for dendrobatid frogs.

The Central Park Zoo, one of the Wildlife Conservation Society's Living Institutions in New York, recently renovated an exhibit for dart-poison frogs. Staff developed a new hollow coconut insect feeder in conjunction with this project. When the exhibit change, coconut feeder, and other enrichments were tested for effectiveness, the coconut feeder enrichment produced the greatest increase in frog activity in traditional and new exhibits.