Farming lessons by a crow

Sowering ravens are not sapient birds, but they've evolved a very complex behavior that can be seen as very primordial farming. It's the first bird and the fourth vertebrate to develop agriculture. Its farming ability probably evolved like in humans from selective feeding and then progressed towards a more controlled plant growth. But unlike humans, this corvid was not able to improve its farming capacity, remaining for millions of years in limbo, without any great improvements to their agriculture society. 

Sowering ravens possess an incredible long-term memory, a very helpful adaptation when you need to remember which plant species can or can't grow in certain months. Raven language is complex, but not as complex as expected: lots of cultural informations are learned and transmitted not by speaking but by watching their conspecifics, while other are just instinctive; this might probably be the social limit for this species. Human communities can be separated into 4 grades of organization: tribe, clan, chiefdom and state. Sowering ravens have slowly shifted from a tribe to a clan organization but failed any attempt to reach a more complex society. Nevertheless, we can't deny the overall incredible capabilities that this bird was able to reach.

The farming methods of this raven are very primitive, since it undirectly protects and rarely directly helps the plant growth. Some cultures use weeding to extirpate weeds, while no observations of mulching or watering were made, at least here in Antarctica. Two ecotypes can be recognized: a steppe tundra and a woodland ecotype. While the steppe-tundra ecotype sustains itself with herbaceous plants and creeping shrubs (strawberries, blueberries, edible grasses, etc.), the woodland ecotype also cultivates higher shrubs (willows, canelos, raspberries, etc.). All plant species are fast-growing, reaching sexual maturity in less than 3 years. Farming activity can be energetically expensive, but it can drastically increase food density, therefore increasing the raven density too. 

They are very possessive of their "cultivated fields", aggressively attacking any possible animal that could ruin their "artificial gardens".  Even a bullduck would flee from a flock of up to 100 large black birds. Different plants are cultivated in different seasons to maintain an abundant food source. Excess food is stocked in hollow trees where the raven colony rest. If food stock becomes scarce, the sowering raven can easily switch its lifestyle to a hunter-gather level, competitively interacting with other less advanced species of corvids. Part of the produced seeds are not eaten but conserved, waiting to be cultivated in the good season.