A Stroll of Curassows, An Asylum of Cuckoos and A Flotilla of Frigates. These are collective nouns. As are the more familiar A Pride of Lions, A Murder of Crows and A Comedy of Errors.
Why Collective Names?
Collective names are often descriptive. Or they can have literary, whimsical, cultural and anthropomorphic qualities.
Many animals have more than one collective noun. Some are specific to the age of the animal such as A Kindle of Kittens for young cats and the more general A Clutter of Cats. Or it may describe an activity. A Paddle of Ducks for those swimming and A Spring for teals just flushed into flight.
A Parliament of Owls’ literary origin is C.S. Lewis’s Narnia Chronicles; The Silver Chair. Cultural roots gives us A Vatican of Cardinals, though I’m sure they are agnostic. We also have A Durante of Toucans. Which refers to Jimmy Durante, a popular comedian from the USA with a trademark huge nose. He was a hit in the 1920’s and 30’s and active in entertainment into the 70’s. Whereas An Embarrassment of Red-faced Cormorants reflects a human sensibility more than the bird’s emotional state.
Many collective nouns are descriptive even for birds that are loners such as A Stillness of Potoos. 
Great Potoo (Nyctibius grandis) by Bryan Pollock ©2019. We also have collective nouns for birds that defy description such as A Confusion of Flycatchers.
While researching collective names, I could not help smiling at the charming turn of phrases and hints at the bird’s natural history. Noel has lamented not having a recording of a Jabiru (Jabiru mycteria) call in all his years of birding. And for a good reason, as they are known as A Silence of Jabirus. Of course Noel is now more determined than ever to capture a call for our eBook. 
Jabiru painted by Bryan Pollock ©2019. Cornell Lab of Ornithology Neotropical Birds website does have Jabiru calls. Labelled a Bill Clatter the “calls” sound like someone running a stick along a picket fence.
Origins of Collective Nouns
Folklore and legends have oral beginnings as do collective names. Luckily for us the proper use of collective nouns separated the Medieval aristocratic gentleman or woman from the everyday yeoman or hobbledehoy. Thus it was part of the nobles’ education and was included in books of courtesy. Several of these books were printed in the 1400’s giving us written evidence of proper collective nouns of the day.
The most influential was The Boke (book) of Saint Albans Containing Treatises on Hawking, Hunting and Cote Armour (heraldry) printed in 1486. The student was instructed on how to behave properly, the niceties of hunting and hawking and the attendant language. Language etiquette included the collective names of wild and domestic animals and birds as well as people and occupations.
Medieval Meanings
Collectives for birds and animals often reflected their use to man, the superstitions and beliefs of the time.
Murder of Crows stemmed from the belief that these black birds were harbingers of death. The appearance of one on a roof top foretold the death amongst those that dwelt within. The omnivorous Carrion Crows (Corvus Corone) of the British Isles and Europe are chiefly carnivorous scavengers. In anticipation of a feast they hung around sick livestock and battlefields. Thus causing people to believe the crows brought on death.
A Tiding of Magpies shows the superstition of magpie sightings. Illustrated in this old rhyme, variations are still sung in the UK today:
One for sorrow,
Two for mirth,
Three for a funeral
And four for birth
The count referring to the number of magpies gathered. 
White-throated Magpie-Jay (Calocitta formosa) by Bryan Pollock ©2019.
Even science of those bygone days contributed to collective nouns. Chloe Rhodes’ An Unkindness of Ravens, A Book of Collective Nouns tells us the origins of A Mutation of Thrushes. Beyond the usual seasonal moulting, medieval scholars may have thought that thrushes shed their legs and grew new ones.
After the Middle Ages
The discovery of the New World, further findings about bird behaviour and the evolution of pop culture inspired collective names for old and new species. The Americas gave us hummingbirds, motmots, toucans, cotingas and manakins.
Collective Nouns and The Neotropic Bird Project
The Neotropic Bird Project’s eBooks have the luxury of digital space. Which allowed us to provide more than the bare essentials for bird identification in our 101+ Common Birds of Costa Rica. As well as in our soon to be released, The Regional Endemics of Central America (working title). Included with each species’ quick specs are cool facts like local Spanish names and collective noun.
When more than one collective noun exists, the most suitable to the species is used. Hummingbirds have many collective names describing their behaviour and often times brilliant colours. For the aggressive Rufous-tailed Hummingbird (Amazilia tzacatl) (painted by Bryan Pollock ©2019), 
we used A Troubling as they will vigorously defend their flower territory by attacking other hummingbirds. We selected A Tune of Hummingbirds for the more passive Violet Sabrewing (Campylopterus hemileucurus) because the males will gather in leks up to ten to call and attract mates.
Painted by Bryan Pollock ©2019.
The Fun of Creating Collective Nouns
When I could not find a collective name, Bryan, Noel and I would put our heads together and have fun creating a one. An example is the regional endemic Prong-billed Barbet (Semnornis frantzii).
Painted by Bryan Pollock ©2019. It has the unusual habit of gathering nightly and sharing a nest hole with non-family members. We came up with A Sleep-over of Prong-billed Barbets.
When a species does have a collective name that does not apply to the Neotropics, we propose a new one. An example is A Season of Tanagers. This collective name makes sense for such tanagers as the Western (Piranga ludoviciana) and Scarlet (P. olivacea) Tanagers. They spend their summers in the USA and Canada. But not all tanagers in the Neotropics are migrants and seasonal, many are year round residents. Such as the Blue-gray (Thraupis episcopus) or Scarlet-rumped (Ramphocelus passerinii passerinii) Tanagers. We often see migrants and residents in mixed flocks at our feeder loaded with fruits (painted by Bryan Pollock ©2019). 
Their acrobatic antics to reach the fruits and their colourful feathers made A Carnival of Tanagers more suitable.
Give It A Try
Whether collective names are based on folklore, poetry or science I think they are a charming way to describe and remember birds. Some nouns originated before the printed word. New ones are added as discoveries are made (the New World being a big one) and new species are identified. A recent (2018) split of the Plain Wren (Cantorchilus modestus) into three separate species make way for new collective nouns. Cabanis’s Wren (C. modestus), Canebrake Wren (C. zeledoni) and Isthmian Wren (C. elutus).
James Lipton, writer, producer and host of The Actor’s Studio authored An Exaltation of Larks, a celebration of language. In it he provides some history behind well known collective names and invites us to create more. We at Neotropic Bird Project fully intend to do this. Particularly as we continue work on The Regional Endemics of Central America. And I invite you to think of new collectives too. I would love to hear your ideas and your thoughts behind them. Please use the comments/contact us section to let us know.
Carey Lee, Cat herder