(formerly Cuculiformes) Growth & development Opisthocomiformes (formerly Cuculiformes) 1 species Hoatzin

Hoatzins are unusual in feeding mostly on leaves Hoatzins are unusual in feeding mostly on leaves. Their crop is exceptionally large and both grinds the food and starts bacterial decomposition. Some regard the Hoatzin as the only ruminant bird. The bacterial fermentation is a rather odorous process and locally the birds are known as “stinking turkeys”.

Crocodillians & the ontogenetic spectrum Precocial to altricial continium (Nidifugous to nidicolus)

Precocial (10% of species) Shorebirds, ducks, chickens Self-feeding Able to regulate Tb Independent The ancestral condition Hatchling reptiles are precocial as are birds of the more primative bird orders including the ratites. Hence precocial hatchlings is reqarded as the ancestral condition.

Altricial (78% of species) Embryonic, eyes closed, naked Total dependence, derived condition

Video clip from Life of Birds of altricial pelican hatching.

Commit this table to memory

Drawing and photos of domestic chick embryos Drawing and photos of domestic chick embryos. Altricials young appear to hatch earlier in the developmental sequence than precocial chicks and thus are more embryonic. http://evolution.berkeley.edu/evosite/evo101/IIIC6aOntogeny.shtml (top fig) http://objectlessons.org.uk/img/BIO000XE4816.jpg (bottom fig)

Gill’s classification of ontogenetic type Species 10 12 78 Gill presents this simplified figure of developmental (ontogenetic) types. The original classification derived by Margret Nice was more complicated and somewhat arbitrary. Note that 78% of bird species produce altricial hatchlings.

Megapodes (mound builders) & Black-headed Duck Total independence Superprecocial Megapodes (mound builders) & Black-headed Duck Total independence

Superprecocial Malleefowl A just hatched Malleefowl chick. Chicks many never see their parents, can fly within a day and are totally independent. Hatchling Black-headed Ducks, which you may recall are obligate brood parasites, are also totally independent of the adults. Malleefowl

Ducks, shorebirds, quail, grouse, murrelets Precocial Ducks, shorebirds, quail, grouse, murrelets

Precocial % of Species 10 12 78 Europeans use the terms nidifugous (=nest fleeing) and nidicolous (=nest loving) rather than altricial and precocial. Leave nest immediately (nidifugous), find own food (although parents “show” food in some species), thermoregulate, albeit imperfectly in some

A precocial duckling.

Precocial Rock Sandpiper Ruddy Turnstone

Precocial Day-old Bobwhite Quail Blue Grouse chick

Loons, cranes, rails & grebes Subprecocial Loons, cranes, rails & grebes

Subprecocial % of Species 10 12 78 Leave nest immediately (nidifigous) and follow parents, are fed directly by parents

http://images. google. com/imgres. imgurl=http://www. birdsasart http://images.google.com/imgres?imgurl=http://www.birdsasart.com/Common-Loon-chick-w-momma%27s-BLACK-neck-_T9J9846-Kamloops,-British-Columbia.jpg&imgrefurl=http://www.birdsasart.com/bn177.htm&h=458&w=650&sz=63&tbnid=JALGnbB1WwAJ:&tbnh=95&tbnw=135&hl=en&start=3&prev=/images%3Fq%3D%2522loon%2Bchick%2522%26svnum%3D10%26hl%3Den%26lr%3D%26sa%3DG

Clapper Rail

Blue Crane

http://www.gdphotography.com/1091.htm Sandhill Crane

Gulls, terns, auks, petrels & penguins Semiprecocial Gulls, terns, auks, petrels & penguins

Semiprecocial % of Species 10 12 78 Able to walk but stay in nest (nidicolous), regulate Tb, fed by parents

Semiprecocial Gull chicks

Semiprecocial Wilson’s Storm Petrel

Emperor Penguin, semiprecocial.

SA 1 Herons & hawks SA 2 Owls Semialtricial SA 1 Herons & hawks SA 2 Owls

Semialtricial % of Species 10 12 78 Gill says semialtricial young are able to walk, but he is incorrect. Unable to walk*, stay in nest (nidicolous), fed by parents, brooded at first

Semialtricial 1 (eyes open) Least Bittern

Semialtricial 2 (eyes closed) Snowy Owl

Songbirds, pigeons, parrots & woodpeckers Altricial Songbirds, pigeons, parrots & woodpeckers

Embryonic, totally dependent on parents Altricial % of Species 10 12 78 Embryonic, totally dependent on parents

Altricial Swift

One-hour old Gouldian Chick http://hometown.aol.com/weldongouldians/GouldianChickDevelopment.htm

Gouldian chicks

All gut, no brain The digestive system of altricial young is well-developed. Altricial chikcs are masters at converting food into tissue. They grow much faster than precocial chicks.

Welty 3rd

Diet-ontogentic link Altricials eat foods that require skill to obtain Precocials feed on small inverts and seeds

Next section examines the items from the arrow on down in this table.

Brown Creeper Least Tern Ruddy Duck Malleefowl Kiwi This slide illustrates the relation between the tissue maturity of hatchlings, as represented by % water. The proportion of nwater in hatchlings is the same as that in the egg. The more mature a hatchling is developmentally (altricial on top, precocial on bottom) the lower the water content and the higher the energy and yolk content of the egg. Takes more energy to build a more advanced chick.

This figure illustrates the sigmoidal pattern of growth exhibited by most birds. There is an inverse relation between adult body mass and growth rate. Small passerines attain adult size in 10-12 days, it takes the wandering albatross 303 days.

Semiprecocial Growth curves for three species that are roughly the same size. The altricial starling grows the fastest, the semiprecocial tern is a bit slower, and the precocial quail is a lot slower. There is a tradeoff between alrticial vs precocial modes of development. Figure it out. The variables include growth rate, energy allocated to the egg, and predation risk.

The Manx Shearwater is semiprecocial the other species are altricial The Manx Shearwater is semiprecocial the other species are altricial. Nestling mass may equal adult mass (starling), exceed adult mass (shearwater & swift), or undershoot adult mass (woodpigeon). In procellarids (shearwater) the excess mass is fat. Adults abandon the young before development is complete and they use their fat stores to survive and finish development.

Same relation as previous figure Same relation as previous figure. The relative mass of altricial nestlings at fledging (nest leaving) is related to diet, as illustrated in the next figure.

Species which capture insects on the wing produce chicks that exceed adult mass. Those that feed on the ground produce smaller chicks. Food hard to get = fat stores, food easy to get = no fat stores.

Altricials The time it takes altricial nestlings to grow from 10% to 90% of adult mass (asymptote). Each dot or circle is the mean for a different species. Dots denote passerines, circles Falconiformes. This log-log plot produces a linear relation between growth rate and adult mass. An arithmetic plot yields a positive exponential.

Temperature regulation Newly hatched chicks very widely in their ability to regulate their body temperature (Tb). A few, such as the Sea ducks, are able to maintain an adult Tb while swimming in water that is near freezing within a few hours of hatching. Most precocial and semiprecocial chicks regulate their Tb imperfectly and need parental brooding for a week or so after hatching.

* These data are typical of early assessments of hatchling thermoregulatory ability. The Domestic Pigeon is altricial, the rest are precocial or semiprecocial. Notice that the ducks maintain their Tb very well whereas the pigeon’s Tb falls over 15 degrees in 20 min. Even the precocial Willow Ptarmigan shows a substantial 8 degree drop. * * * Semiprecocial

Thermoregulatory Index The % of adult Tb-Ta gradient maintained following 30-min exposure to 20ºC Studies that have examined the ontogeny of thermoregulatory ability have often exposed chicks and adults to a low temp (often 20 C) for 30 min and expressed the chick’s ability as above.

Thermoregulatory Index Body temp Gradient Start End Tb-Ta Adult 40ºC 40ºC 20ºC Chick 40ºC 22ºC 2ºC Chick’s 2ºC gradient is 10% of the adult’s gradient

Note that although the altricial starling is initially much poor at regulating its Tb it grows rapidly and soon overtakes the precocial quail.

House Martin House Sparrow Circles = house martin, dots = house sparrow. These two passerine species exhibit the usual sigmoidal pattern in development of thermoregulatory ability with the House Martin maturing more rapidly than the sparrow. House Sparrow

Growth & development Ontogenetic types Diet-ontogenetic link Growth rate patterns Tissue maturity of chicks Egg contents