DMC #20: Here's the Anser!
(formerly called Follow the feeder #1)
This is the final cache of a 20-cache circuit, consisting of 16 new + 4 existing caches (adopted from Santos L Helper) which takes you anticlockwise through lovely mixed countryside from near Denton village across to near Middleton hamlet and back.
See DMC #1: Intro & Start for background info on the series, a map (also found in this cache's Gallery) and parking waypoints.
The cache, was previously part of the 5-cache Follow the Feeder series but has been dropped from this as it is now out of the new cache sequence. The FTF series remains as a reduced 3-cache series.
The cache is hidden on the bank of the Skifra Beck as it flows out of the West Park Woods en route to join Hepper Carr Beck and on to the Wharfe.
A 30+ gaggle of these large birds was grazing in the fields south of the cache location.
The ancestor of most domesticated farmyard geese, the greylag (Anser anser) is the largest and bulkiest (2.9-3.7kg) of the wild geese native to the UK and Europe. In many parts of the UK it has been re-established by releasing birds in suitable areas, but the resulting flocks (often mixed with Canada geese) found around gravel pits, lakes and reservoirs all year round in southern Britain tend to be semi-tame and uninspiring. The native birds and wintering flocks found in Scotland retain the special appeal of truly wild geese.
They are listed in Schedule 2 of the Wildlife and Countryside Act, meaning they can be killed or taken outside of the close season.
They are easily seen all year round in lowland areas, sometimes even in suburban parks with lakes but especially on low-lying grassy fields in river valleys - as here.
They are largely herbivorous and feed chiefly on grasses. Short new grass is more nutritious and they are often found grazing with sheep or cows. Because of its low nutrient status, they must feed for much of their time; the herbage passes rapidly through the gut and is voided frequently. They may also eat tubers (eg. potatoes), berries and water plants. In winter they eat grass and leaves but also glean grain on 
cereal stubbles and sometimes feed on growing crops, especially during the night. They may also feed on oats, wheat, barley, buckwheat, lentils, peas and root crops. Acorns are sometimes consumed, and on the coast, seagrass may be eaten. They also eat small fish, amphibians, crustaceans, molluscs and insects.
They usually have long-term (probably life-long) monogamous relationships, but 5-8% divorce and re-mate. Birds in heterosexual pairs may be promiscuous, despite their mate's opposition.
Homosexual pairs are common (14-20% of the pairs may be ganders) and behave like heterosexual pairs except that the bonds appear to be closer, based on the intensity of their displays.
Same-sex pairs also engage in courtship and sexual relations often assuming high-ranking positions in the flock as a result of their superior strength and courage - possibly serving as flock guardians. The orientations of the birds are flexible, as more than half of widowers re-pair with a bird of the opposite sex.
They nest on the ground among heather, rushes, dwarf shrubs or reeds, or on a raft of floating vegetation. The nest is made of pieces of reed, sprigs of heather, grasses and moss, mixed with small feathers and down.
A typical clutch is 4-6 (initially creamy-white but soon stained) eggs mostly laid on successive days and incubation by the female starts after the last one is laid and which lasts about 28 days, while the male remains on guard somewhere near.
The chicks are precocial and leave the nest soon after hatching. Both parents care for them and they soon learn to peck at food and become fully-fledged at 8-9 weeks - about the same time as their parents regain their ability to fly after moulting their main wing and tail feathers a month earlier.
Immature birds have a similar moult, and move to traditional, safe locations beforehand because of their flightless vulnerability.
They are gregarious and form flocks which means that the vigilance of some individuals allows the rest to 
feed without being constantly alert to the approach of predators.
After the eggs hatch, some grouping of families occur, enabling them to jointly defend their young by mobbing or attacking predators. After driving off a predator, a gander will return to its mate and give a 'triumph call' - a resonant honk followed by a low-pitched cackle - with neck extended parallel with the ground. The mate and even unfledged young reciprocate in kind.
See here for more information.
See videos here (good general info), here (pair in the spring, preening), here (huge creche spooked by cow), here (pair with goslings), here (slow-mo close-up), here (nesting in York station during Covid-19 lockdown), and here (How to ID grey geese on land, water and in the air).
