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.

Come on baby, let's do the twist: the kinematics of killing in loggerhead shrikes.

Shrikes use their beaks for procuring, dispatching and processing their arthropod and vertebrate prey. However, it is not clear how the raptor-like bill of this predatory songbird functions to kill vertebrate prey that may weigh more than the shrike itself. In this paper, using high-speed videography, we observed that upon seizing prey with their beaks, shrikes performed rapid (6-17 Hz; 49-71 rad s) axial head-rolling movements.

Functional morphology of hummingbird bill tips: their function as tongue wringers.

Nectarivores are animals that have evolved adaptations to efficiently exploit floral nectar as the main source of energy in their diet. It is well known that hummingbirds can extract nectar with impressive speed from flowers. However, despite decades of study on nectar intake rates, the mechanism by which feeding is ultimately achieved - the release of nectar from the tongue so that it can pass into the throat and be ingested - has not been elucidated.

Hummingbird tongues are elastic micropumps.

Pumping is a vital natural process, imitated by humans for thousands of years. We demonstrate that a hitherto undocumented mechanism of fluid transport pumps nectar onto the hummingbird tongue. Using high-speed cameras, we filmed the tongue-fluid interaction in 18 hummingbird species, from seven of the nine main hummingbird clades.

Nest-building behavior of Monk Parakeets and insights into potential mechanisms for reducing damage to utility poles.

The Monk Parakeet (Myiopsitta monachus) commonly uses utility poles as a substrate for building large, bulky nests. These nests often cause fires and electric power outages, creating public safety risks and increasing liability and maintenance costs for electric companies. Previous research has focused on lethal methods and chemical contraception to prevent nesting on utility poles and electrical substations.

The hummingbird tongue is a fluid trap, not a capillary tube.

Hummingbird tongues pick up a liquid, calorie-dense food that cannot be grasped, a physical challenge that has long inspired the study of nectar-transport mechanics. Existing biophysical models predict optimal hummingbird foraging on the basis of equations that assume that fluid rises through the tongue in the same way as through capillary tubes. We demonstrate that the hummingbird tongue does not function like a pair of tiny, static tubes drawing up floral nectar via capillary action.

Feeding mechanisms: Hummingbird jaw bends to aid insect capture.

The upper jaws of birds, unlike those in many tetrapods, move relative to the skull and are often flexible along their length, whereas the lower jaw (mandible) is usually a rigid structure formed by the fusion of several bones, flexing only where it meets the skull. Here we describe a previously unnoticed mandibular bending movement in hummingbirds, in which the distal half of the mandible is actively flexed downwards and the gape widens to catch flying insects. The hummingbird is thought to have developed a long narrow bill as it specialized in feeding on floral nectar, but the bird's need to supplement its diet with insects must have contributed to the surprising flexibility of its jaw.

Sexual size dimorphism in red-necked phalaropes and functional significance of nonsexual bill structure variation for feeding performance.

Sexual size dimorphism is widespread in shorebirds, yet no tests of the assumption that such size dimorphism extends to functionally significant dimensions of the bill exist. This report presents tests of: (1) the assumption that sexual size dimorphism extends to the feeding structures in sexually size dimorphic bird, and (2) the hypothesis that bill-size variation influences feeding performance in Phalaropus lobatus, the red-necked phalarope. Discriminant function analysis revealed that the sexes of this species can be distinguished on the basis of five body size/bill length variables, but with low accuracy in sexing of females because of misclassification of small females as males.